la grave is pretty gnarly dude, make sure you have all your AV equip.
Les sept laux is really close and is full of students who live in grenoble. Les deux alpes is pretty far but definitely drive-able. There are quite a few others but i can't think of em now.
message: rastafarider he lived there for a bit and knows the ropes better than most on this site.
good luck and enjoy, some of the best times i had in europe went down in GNB.