I take my old 486's 200-500 mhz and p-2s and i ussually give them away to friends and family members with young kids .
I keep the programming simple and load a pile of children games on them .
Dr seuss abc, blues clues, reader rabbit just to name a few .
my own son (who just turned 3 in january) already knows his abc's, numbers to 10 (he can read them and is starting to read the words ) along with being able to navigate thru all his games by himself .
its rewarding in its own way .
Im always taking hard drive contributions though, 2-6 even 10 gig is plenty for a young one .
I built 7 new pc's last year and gave away 3 , ive got one more to get together to give away to a needy young girl but im still shy a good hd. (ive got a 2 gig that rattles and a 129mb drive laying around basically junk)