When i was 14, my mate had a birthday at his house, the usual thing at that age - pizza, films and then everyone crashes the night. Some people had just started smoking cigarettes (to look cool probably), and one guy, stu had been smoking out of the back window, and had dropped the fag and burnt my mates carpet (even though my mates had repeatedly told him not to smoke near the house, never mind in it). He showed no remorse, and we were all pissed off with him...anyway, it was a saturday night, and stu had a paper round at 6am in the morning, so he set the alarm on his watch to 5:45am and put it next to his head so he would wake up when it went off. He fell asleep around 1am, but the rest of us were all still awake, and we had a plan.
Firstly, we went outside and let the tyres down on his bike that he needed to cycle to the newsagents in the morning, and then hid his trainers. We then went inside and changed the time on his watch and all the other clocks in the room to 6am (it was now about 2am, and he was still asleep).
Then one of us woke the guy up going "Stu mate, its 6am, you've slept through you're alarm"...he shot up, checked his watch and the time and was like "shit shit, i've gotta run", so he runs into the hallway (it was still dark outside at that time in the morning as it was november time, so its hard to tell the difference between 2am and 6am) - cant find his trainers, panicks for a bit, obviously knowing we've hidden them, but what can he do! So he runs bare footed out to his bike, only for the tyres to be flat (we are all watching from the living room window) - and we see him start pushing the bike out of driveway.
He was gone for over an hour, before he returned...obviously he had got to the newsagents and it hadnt been open,waited and then gave up and come back very confused and pissed off - he was bloody furious with us all when he worked it out, but it was so so funny to watch the panick. Kids can be cruel i suppose, but then he'd deserved it for the ways he'd acted earlier in the night and it was a pretty well planned prank 