Release 4.1 of Brain Workshop introduces some GUI tweaks and a new sound theme (piano notes instead of spoken letters). I finally gave it a try and was able to record sound via recordmydesktop with the help of this config guide.
The rules of the game are: watch and listen and press one button if the same field becomes active as it was n (a number) rounds before or if the same sound appears as it was n rounds before. I'll definitely 'play' this brain-trainer some more. :)
Are you into web-based strategy games? Epoch is an sci-fi/space type one. Development started in 2002 and it is open source.
According to this forum post, Epoch's team is now working on an OGRE-based 3D game with the same setting, but it might take some years.
You might have heard about the "open source", GNU/Linux-based, 250$ EVO Smart Console. Lol. 100% vaporware.