You can start lurking the M68K Liberation Army website. (yeah, they accept PPC Mac users too over there) Lots of old-school discussions - you are bound to get some ideas there.
http://68kmla.org/forums/But I am not quite sure what you'd expect as a use:
Simple audio editing
Email
Playing Marathon and discovering how much Amiga owned.
Simple Photo Editing
Browsing
It still has life in it but in my opinion if you put OSX on it - just use terminal apps and fuss through life with OS9 on the thing.
