My older brother is one of those people that will dedicate a lot of time to wasting time. When he doesn't feel like working or studying or whatever he's supposed to do, he'll find something to distract him from work. This usually results in the planning of elaborate pranks. He plans pranks for days or weeks just so he can really catch someone off guard.
I think this happens mostly at work because of his boring job. He once spent an entire afternoon covering every item in a coworker's cubicle with aluminum foil. He wrapped each individual pen, every binder in the cabinet, and even the paper clips left on the desk. He was ridiculously meticulous. And he bought the foil two weeks in advance in case the opportunity came sooner than expected. Not to mention the fact that he spent 40 dollars on it. He really likes messing with coworkers, too. His favorite thing to do to new people at work is email them when he knows they're at their desk. All he sends is "Turn around." Then he walks to their desk quietly and stands behind them until they get the email. It never fails to freak people out. And since he knows the network at his office is super slow, he always makes it to their desk before the email does. I wish he could get some pictures of their faces when they turn around and see him towering behind them.
One time he waited after hours for a coworker to leave, and then dismantled his PC and put a cell phone inside. He made sure the volume wasn't too high, but he set the ringtone to circus music. Then he put the PC back together and back in place. Then when the guy came in the next morning, my brother called the cell phone every five minutes. And it took an hour before the guy realized the music was coming from his desk. He pulled open every drawer, moved his computer, his monitor, his printer, and even crawled under his desk looking for the source. And once he unplugged everything and broke a sweat in his work clothes, my brother stopped calling. So after the guy decided he had finally eliminated the source and he'd moved everything back, he started calling again. It drove the guy crazy. And worst of all, my brother got everyone else involved too. So everyone else in the office pretended they couldn't here it. But the volume was so low, that the guy wasn't even sure he could hear it himself. Eventually he quit working and went through each item in his desk until finally he pinpointed the source. So after he dismantled his own PC, he finally found it.
In his defense though, the guy is a super cool guy. He would never do that to someone else, and he's always been nice to everyone he meets. I definitely didn't... I mean, he definitely didn't deserve that. Okay, fine... it was me. I still have to think of a way to get him back.