Not really a prank, but a sled game that we kinda developed from the "kill switch" prank, is playing tag while boondocking. You have to get close enough to touch another rider and then they're it. Sometimes you have to cut a sled off in the woods, dismount and run over to tag them, which sometimes turns into a foot race in deep snow.
Sounds kinda retarded, but it is actually really fun!! Last year I cut my buddy off and he jumped off to run so I moved my old beater sled out of the way and jumped on his new sled and took off!
Guess that could be considered dangerous, so kids don't try this game at home ok!