I've also hotboxed a tent, which was fucking great. I've done cars and the usual, but my best hotbox story is from Freshman year at college, where me and my girlfriend went into my walk-in dorm closet and smoked a blunt. When we opened the door, there was like a fucking mushroom cloud pouring out, but it as a week before people were due back to the dorms, and no one was really there, except for a few stoners who we had smoked with in a previous semester. The smoke was so thick in there that we couldn't even get a good grope of make-out session; we just had to leave.