DC Rainmaker Open House 2023 Recap!

Two weekends ago we held the 8th annual DC Rainmaker Cave Open House, where a couple hundred people descended upon the DCR Cave for an evening of sports tech geekery. As usual, they could explore the entire DCR Cave/Studio, and we supplied the free beer, other drinks, food, and even sweet gift bags to everyone in attendance.

The day was divided up into two parts. First was the morning run, usually about an 8-10KM, looping around some portion of Amsterdam. Then the main event is held in the evening, at the DCR Cave. The idea being that many folks make a weekend out of it, giving reason to visit Amsterdam as a city during the holidays. The whole day is then free for someone to do touristy things (or, just drink beer). In fact, there were people this year flying in from Australia, South Africa, Namibia, India, United States, Canada, and countless more within Europe. All to visit the Netherlands, despite the lack of tulip fields this time of year.

With that, let’s get into the recap!

The Morning Run:

As has been the case since the first Amsterdam Open House, we’ve met at All4Running, a running shop, just at the end of Vondelpark. The store is the perfect spot to start the run, especially in cases like winter where someone needs to add a forgotten pair of gloves or hat. As has also been the case every single year, the weather in Amsterdam got downright cold for the open house weekend. Obviously, this isn’t Finland cold, but each year the weather is perfectly functional till the week of the Open House, then it freezes everyone, before getting warm again the following week (which also happened).

In any case, a quick game plan overview inside, and then out we went for the group photo. This is the first of many tests in ‘not blocking the bike path’, which runs directly in front of the All4Running door. Thankfully, nobody got clipped this year – at least during this portion.

From there it was into Vondelpark as one giant group. This part works out fairly well space-wise, as obviously it’s super-wide. For the morning run we had about 50 people or so brave the elements, which is one of the higher run turnouts we’ve had. Again, planning for the win here!

It was a no-drop run, so we kept it together as one big group, banana included:

Paul, the banana, picks up trash on the ground along the way, with thousands of kilograms picked up each year. You can follow along on his adventures on Instagram.

From there we meandered into the pretty canal areas a bit, sadly, I didn’t take many good photos on this run.

After that we backtracked towards the Rijksmuseum for a group photo:

The iAmsterdam sign is long-gone (we lucked out in 2018, as they removed it the day after that run), but the museum still works as a good backdrop!

From there we meandered through quieter areas of Amsterdam, attempting to avoid tight sidewalks/paths, but mostly failing. Don’t worry, we only required one Urban Arrow cargo-bike ambulance pickup, when one runner attempted to fly. It was a very short-lived flight, albeit, she enjoyed the Des cargo bike ride back.

Oh, and it’s critical to point out Harry was once again in attendance! He has made every single Open House run since the first one Paris back in 2014.

All in we clocked up about 9KM, per Strava. Sometimes we do a loop around the stadium (inside or outside), but with the larger group I tweaked the path a bit earlier in the run to divert off of some of the skinner paths to connect those two areas, thus skipping that this year.

Oh, and again, a huge thanks to the All4Running crew for both the space and their hospitality.

Definitely give them a visit if you’re in town (or, if you’re a local), for all your running-goody needs!

Evening Open House:

This was easily the biggest DCR Open House we’ve had to date – largely on account of opening it up a bit earlier, and then probably also better update/managing of the registration/waitlist/etc on our part – letting more people get a spot.

In any event, the…well…event, started around 7PM at the DCR Cave. Folks were free to wander around and check out the tech, including jumping on the various trainers and bikes sitting in the main studio area. Essentially the downstairs of the DCR Cave is a big open space (which I mainly use for long-term storage/events/treadmills), and the upstairs is the main studio/office/storage area. Here’s the downstairs portion.

We had a bar set up in the back near the gondola, with both regular beer/wine/soda/water, but also more importantly, a custom IPA made by one of our brewmaster friends. It was officially named “IP-rAy” (obviously, I don’t come up with these things, that’s the territory of my wife).

And to top it off, we also had custom DC Rainmaker beer glasses:

Here’s a closer look:

Also downstairs was a giant Spanish ham leg, which both DesFit and our friend Julio volunteered to ‘carve’ for many many hours.

Here’s what it looked like when Des first started:

And of course – just lots of good conversation, about both tech and non-tech things alike!

Meanwhile, upstairs was all about the gadgets – with folks able to try a number of bikes and trainers. This here being the KICKR BIKE SHIFT, running Fulgaz:

As well as the Zwift Hub One (the new one with the Zwift Cog). And then also the KICKR Bike V2, in case you wanted to compare the more expensive BIKE V2 to the less expensive but newer BIKE SHIFT.

Of course, plenty of conversation as well – including chats with fellow sports tech YouTuber’s Des & Matt Legrand:

Speaking of which, here’s Sports Tech YouTuber Matt Legrand, he was hanging out on the stairs – deciding his next move, when caught by the camera.

Also upstairs was the wall of bikes. As always, the Canyon Grail handlebars get quite a bit of attention, even these many years later. Or, maybe it’s all the bike computer mounts on them.

Soon though it was time for the Q&A and prize giveaways. So, this photo was as we were rounding people up downstairs before we started the good stuff!

We alternated a slate of prizes/giveaways we had, along with doing what is essentially a podcast-style Q&A from attendees. We even recorded it this year, albeit, I haven’t gotten around to editing it.

On the prize goodness, we had a few awesome companies step-up and provide boatloads of items. Both major prize bags, but also goodie bags for everyone as they left.

First up is Precision Fuel & Hydration. They make the various hydration/nutrition products that both my wife and I use for our endurance training and racing (see our Gear I Use lists). And yes, we still buy all our own stuff! They’ve sponsored a few DCR Open House events over the past few years, and we’re super grateful to them!

Then we’ve got Ass Magic. They make chamois cream which my wife swears by for her riding. She loves it, and has entirely changed her outlook on riding (whereas before she didn’t entirely love long rides). Ass Magic also contributed to our gift bags for all attendees, everyone get travel snap packs of both chamois cream and anti chafe cream. The Girl stashed both of said snap-pack products in her transition bags this year while racing. Good stuff!

And lastly, thanks to Brooks Running as well, who also provided a bunch of giveaway items for prizes!

Again, I’ll try and get that 75-minute or so Q&A session edited up somewhere. At least for DCR Supporters, if not everyone. Especially this moment here with some women’s-only giveaways (involving throwing of things) that ended…hilariously.

Finally, I need to do a huge thanks to Jonas, who volunteered to grab one of my DSLR cameras and take the vast majority of these photos. In fact, about 1,100 photos in total! Insanity, but also amazing. Almost as amazing as our near identical shirts we both independently selected:

Now, if you missed the behind the scenes tour that tech YouTuber Matt Legrand did, he came by after the event as well, and we poked and prodded at the DCR Cave:

Thanks again to everyone who came out, we really appreciate it! And, for historical fun purposes, here’s links to all the previous editions

The firstsecondthird,  fourthfifth1st summer edition, sixth, and seventh DCR Open Houses!



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  1. Bryant Likes

    Looks like a great event!

    Quick somewhat related question. In the Who is DC Rainmaker video you talk a little about your hot box that you set up for your wife’s heat training. I was thinking of doing something similar and was wondering if you figured out how to make it work with Garmin’s heat adaptation tracking? Do you have to not just use Zwift and use a Garmin to record rides in the hot box for that to work?

    Thanks for any tips! :)

    • Thanks!

      Yup, I’m gonna write/video something up on the Heat Box. Not quite sure if I’ll knock it out in the next few weeks or it’ll spill into January.

      In our case, I put the Zwift screen outside the heat box on an Apple TV, thus using the remote instead. It’s only like a meter or two away through relatively thin plastic sheeting. Though a few times my wife just used her phone instead, and I used an iPad once on a treadmill too. Worked just fine.

      For heat acclimation data, both of us used CORE sensors. That gave us a relatively good ballpark of where we stood in terms of total time in heat zones. Obviously one can quibble a tiny bit on super-exact accuracy there, but the thing is, you really don’t need a CORE sensor to figure it out. Most of it comes down to looking at drops in HR, relative to effort, and then spending usually no more than about an hour in there.

    • Here’s a picture of it, including one of the days with a humidifier running to increase humidity.

  2. Robert B

    Hi Ray, any plans to put the glasses on teespring? 568ml or some other obscure measurement? Cheers 🥂 my cup is lonely

    • Yup, I’ll get that added to teespring! I know we’re somewhat limited on how low the pricing can be there, as we usually only barely break even on the stuff there – yet still seems expensive. But will circle back once the listing is approved.

  3. Bruce Burkhalter

    Looks like a ton of fun! So good of you all to host the event.

    Do you still have to move out of the space? Did you find a new place?

    • We’ve had a temporary stay of execution. Just yesterday in fact we got the confirmed/signed 6-month lease extension, till June. Which is good, cause I was really hoping we weren’t gonna have to move out of this place in the next 10 days.

      It remains unclear exactly when they’ll tear down the building, but perhaps they’ll keep extending it. So for now we kicked that can down the road.

  4. Jay

    Interesting representation from a diversity perspective. Guess the sport still has a long way to go, demographically.

  5. Matt

    The hanks for hosting Ray!!! Such a fun time!