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.