same problem here: my notebook (Fujitsu-Siemens S6010 i830 ) and my PC (Radeon 9200) show the same behavior. It also happens with some of the screen-savers, most often with the OpenGL examples.
Tux racer is exhibiting some strange symptoms. 1) It doesn't alway run. Sometimes it flashes the screen, i.e. it goes into full screen mode, and then it quits. Immediately rerunning the program can then work. Sometimes it takes three retries. 2) At the end of a practice run, it doesn't stop on the screen that says what my score was but jumps to the best score screen.
How can I help debug this. It wasn't happening last week on kernel 351, but is happening on kernel 356 but otherwise up to date.