Fresh install of CR and Ubuntu 14.04, start the game and get a resolution which makes your computer go wild.
Can be easily fixed by editing ./clonk/rage/config file of course (changing resolution from 800x600 to anything a bit higher).
Probably happens because CR is not that good in detecting resulutions (like 3200x1800, which my laptop has). This has been improved in OC and might be backported?