Running Arch Linux "Duke", just did a pacman -Syu recently (system upgrade)
Using the `testing' X11 and libgl/mesa libraries, tremulous causes your X server to crash. reverting to 6.x libgl and mesa libraries, and the stable X fixes this problem. Other GL apps don't make X segfault however.
Time to reinstall your gfx-drivers after the upgrade.
Quote from: |pl0x|InakiUsing the `testing' X11 and libgl/mesa libraries
Well duh! This is almost to be expected.