Finger training?

I was just wondering if there any finger exercises I could do during the day (when im at work wishing I was at home playing...lol) that would help buid stronger fingers and cordination? Any sudgestions?

i use a rubber hand or my stress ball several times throughout the day.

would love to hear more suggestions from experiences musicians though.

I always tend to do a simple exercise when I'm bored.

I alternate two fingers at a time. I'll alternate index-middle, then index-ring, then index-pinky, hit 5 times each finger. Then I reverse it.

Bugs the life out of my co-workers tho lol