Nothing is as timeless or as bonding an experience as annoying the hell out of your friends by massively inconveniencing them. When your friend (or maybe not-so-close friend) leaves their room unattended and unlocked for the weekend, this will give you the chance to reach this schadenfreude @@checked link@@nirvana. Here are a few easy ways to manage that.
Cellophane: A pain to wrap your food in but an effective means of bothering your roommates. A few layers on a laptop, chair or bed are more than enough to stymie your roommate. Set aside a weekend and wrap everything in their room if you want to make a memory. Or try this. Or even this. @@make sure to remove these last two for the print edition@@
Duct taping: Duct tape allows for what cellophane does not: adhesion. With a couple strips, you can attach a phone, all of your roommate’s pens or other small, important objects to a nice patch of ceiling. Be aware, however, of the damage that the adhesive side of duct tape can do to sensitive electronics and screens. You want to prank your friends, not start a blood feud over damaged property. Both are funny, yes, but you’ve got a social life to think about.
Piling chairs:  With a little planning ahead and a few more sets of hands, you can move a few stacks of chairs into your friend’s room. Stacking on wide surfaces like the floor or the bed is easy enough but be sure to get the balance right on the more precarious stacks. This is where that high school physics class might come in handy.
Cups: Never underestimate the power of a hundred cups filled with tap water set on every available surface. Though filling every cup takes a while, the outcome is worth it, as this is one of the most problematic of these pranks to defuse. Just be sure not to wall yourself in when you’re placing all of them down!