SameGame? for GNOME.
This little timewaster apparently comes from the Apple Macintosh, but I hadn't seen it pre-GNOME. You have a grid of balls of three colours, that you can remove in clumps of the same colour. You get more points the bigger your clumps are, and a bonus if you get rid of them all.
(If you're interested, the rest of the screenshot is GNOME 0.13. ;)