highest i've been, hmm. me and 2 buddies rolled up 12 joints and hotboxed one of their cars (mazda protege, its rather small). by the time we finished em all off i could hardly see my friend sitting in the back seat. Everytime i took a breath it felt like i was taking a hit...it was crazy. So i fell asleep in the car filled with smoke for about an hour and woke up realllllly high.