Sounds a lot like my new job. Things sail over the walls, Rubber band fights are the norm. Leaving your computer unlocked is an invitation to have your screen saver, home page, and wallpaper changed to something disgusting or disturbing. Going on vacation means your cube will be pranked. Finding out who the ringleader is appears to be mandatory and retaliation is encouraged. Group participation in cube pranks is almost always the rule, and no one is immune. The general manager of the office participates in and encourages pranks. Ball-breaking is an every day way of life for the office.
It’s juvenile. It’s unprofessional. It’s the kind of stuff 12 year-olds would do. And after beating your brains out for hours trying to fix some obscure bug in the code because your deadline is in two days and your project manager is an ass, and you just have to unwind, it’s just right.
I’d hate it for some wet blanket to show up and spoil the fun for the rest of the office.