I've always heard those little spasms/twitches are from too much caffeine. Also, I think I read once somewhere that low potassium levels can cause them, too. Eat a banana and see if that helps.
I don't think it's anything to worry about---just an annoyance.
No on the alcohol question but for the vitamins, thanks, it's worth a shot!
I have that problem in my legs and eyelids mainly when I don't get enough sleep. I have had it happen in my arms as well, but not as often. I also agree about the vitamins ... try increasing your sleep and do some research online to see what your recommended daily vitamin intake should be and see if that helps out at all.
Do you drink alcohol? I know that this can happen from withdraw, even for someone who is a moderate drinker?
Are you on a good high-mineral vitamin? Something is tickling in the back of my brain about taking potassium to ease this problem. Sorry but I can't remember more. It wouldn't hurt to try it, though. Good luck!
I have no clue what causes this but sometimes my eye will do that. It is wierd because I feel it happening and only on occasion I can catch it doing it while I wait to see in the mirror. I would like to know what that is also.