Always on the lookout for the next 'killerapp', I'm looking for the next fun lil' toy to install. I'm really only interested in the linux ones, but as most people don't use it (yet!) you can taint the thread with closed source software - just label it as win*(crap) only.
so what are you fidgeting with?
mplayer - plays every media format I've thrown at it. period.
celestia - interactive 3/4D solar system/galaxy simulator/browser.
kismet - hey look! an open WAP!