Plan9:
Yeah, re-reading my post fails to yield me referencing any "finger muscles". The rock climbing idea is a good one. I've tried the indoor rock climbing bit a few times and it makes you sore in fun places
seizei:
That's pretty much exactly what I'm looking for. Awesome! I'll go pick up some jars today when I'm at the mart. Also, I do practice kung fu and that's sort of how this whole thing came up. I just started learning a tiger form.
bundy:
Another good suggestion!
jimk:
Actually, I do play the bass guitar with an exaggerated action so that it requires about 5 time the amount of usually required pressure for fretting the strings.
Lunchbox7:
Hahaha, I like the pizzeria idea!