Well, the most awesome thing you can probably do on it is use it to speed up everyday stuff on your Amiga. There quite some PPC builds of everyday tools (archivers, mp3, etc) that you can install on your system and use in place of the "regular" 68K tools.
That should make your system faster in overall daily use.
Other than that, sell it while it still works and buy a nice laptop or iPad for the amount you sell it for ;-)