Here's a guy playing with a supercritical CO2 pressure vessel on a table (seems a little brave to be shaking something at such high pressures!) https://www.youtube.com/watch?v=2d7RGQMCX24
There is a Help->Rules link on all of the puzzles linked here. It can be a little tricky to decipher them if you're coming to them completely brand new, however. I mostly use them as a refresher.
I actually had a concurrency bug that I was able to capture with rr: an MPI job where I only ran rr on rank 0 and managed to figure out where a different send/recv ordering was causing issues. In fact, it was also a Python model that ties in with a lot of native code generation, so quite a complex issue.