you can also get the crank off (a built and functional bike)

by taking out the middle bolt one full turn,
then go ride the bike up hills until the crank loosens a bit. undo bolt another
turn and ride some more until it is evidently loose. it won't
hurt anything as long as you remember not to -really- ride like that

if the crank it really stuck on there it could take forever to do...and it may still
stay stuck.

Wow, this is some bad advice. It will oblong the hole in the crankarms. Only do this if you don't want to use the crankarms again.