Super Mario 64 Glitches

Cap in Hand On Snowman's Land
Go to the Snowman's Land level upstairs. Get your cap blown off by the giant snowman. Go over to the teleportation tree (it will warp you to a spot). Then walk a little ways and come back to warp again back to where you were. Do this several more times. Go get your cap and when you pick it up it will be in your hand.