After a hardcore gaming session in my friend's single bed dorm the two of us decided to get some air. The moment we stepped out of his dorm I exclaimed: "I had no idea you were that flexible!". His dorm neighbors have been questioning his sexuality ever since
I convinced a coworker of mine that George Washington was in fact not the first president of the USA. And this was not a " dumb " coworker, I was just really convincing and confused the hell out of her Good times.
Knowing full well he had an important meeting with his supervisor next day we drew a moustache, monacle and bit of goatee on one of my housemates... Then topped it off with "BALLS" on his forehead. In permanent marker. It wouldn't come off for a week.
Rang my brother in law up room to room on the hotel phone in portugal and using my best portuguese accent informed him that he had could come down to the front desk to collect his free massage. .....he actually went down to collect it, he was not amused. My wife laughed so hard she actually laid an egg.
This story involves World of Warcraft, but don't let that put you off, it wasn't wow-ish in nature. The Random Group Finder tool in warcraft puts you and any friends you're grouped with into a random dungeon with strangers from other servers. These strangers often vary wildly in age, nationality, competence and attitude, so lulz are often had. TL;DR for those who can't decipher the images below: I and two friends were rolling random dungeons and not taking it very seriously, trivialised as they are now by current gear. We three merry trolls were placed with a very impatient chap who immediately requested "fast plz". You hear this a lot, usually from kids whose bedtime is approaching. We had no intention of going fast. Instead, we made an impromptu decision to sit down, light a fire and begin telling stories, over his txtspk protests. (To our delight, the second stranger caught on and played along with it.) The caps don't convey a time scale, but this went on for about five minutes. Lesson: don't be impatient and rude to people you depend on to proceed.
In computer programming class, my friend left his computer for a moment. So I did a search for *.exe and then hit ctrl+a, and open.
at my highschool i would hit ctrl+alt+arrows to change the screen orientation on several comps in the library. lulz were had.
In high school our network administrator used a program to control our computers when we were hogging all the bandwidth. However we found that when he did if we opened a full screen view of the command prompt with (which was blocked but circumvented using .bat files) it would prevent him from controlling us. He got so pissed one day he just banned all of our accounts in the class.