I'm a bugger for winding people up and rarely kop for it myself as the penny usually drops b4 i become the victim but love it when someone is taken in hook line and sinker.
Take today for example, during any breaks at work I usally nip in the workshops for a few games of darts, we have competitions where the first to twenty wins.
I say 'we' there are only three of us and have been playing for the last couple of yrs, whoever wins a 'twenty tourny' has to make up a new game and rules for the next tourny.
As I had won the last tourny I made up a new game and one of the rules was (bearing in mind the doors are usaully open in the workshops so there are usally fly's in the place) if you spear a fly with a dart you automatically win the current game and gain 5 extra points.
Its never going to happen but it's a laugh as flys pass the dartboard and we say 'oooooh nearly got the cnut!'
Anyhow one of the lads was going through a bad patch and went on a run where nothing was going right, whereas my other workmate couldn't do anything wrong; even if he was missing it would bounce off another dart and find its way into a double, this was really winding the other one up. Me I don't give a fcuk and just enjoy watching those two arguing all the time.
Anyhow in this particular game workmate number one (the struggler) started to get his act together and was pissing it only needing one number to win, whilst myself and the stuffy fella (workmate numero 2) were miles behind.
Then it was workmates numer 2's turn to throw, he chucked his darts and as he threw the last one he said "I'm sure i clipped something then", then walked towards the board proclaiming "fcuk me!! I've bagged a fly".
Straight away I clicked what was going on, the cnut had got a dead fly from somewhere and put it on his dart b4 he threw it, but workmate number 1 wasn't so quick on the uptake (probably because he was an inch of winning and turning his fortunes around) and proceded to start WW3, I just played along with it pissing my sides but he was so wound up and calling him every cnut in the book he didn't see it

Even when we were both laughing in his face he couldn't see it and eventually we had to tell him.
I suppose it's one of those where you have to be there to appreciate it but it was fun.
I bagged somebody else in work the other week but its a long story so I'll tell that another day.
A quick one was when i was working with a fella who became a shop steward, it went to his head and he started coming in wearing trousers and shirt walking around puffing his chest out like he was summat.
He then resorted to coming in work with a Briefcase instead of his usual sports bag or if he had a meeting taking a leather A4 size wallet with him containing the documents he needed.
This particular day he wouldn't shut up and kept going on about this important meeting he had, he got all his documents together and put them in his leather wallet then fcuked off for a piss before he went to the meeting leaving the wallet on his desk.
While he was gone i took out all the documents and replaced them with porno magazines.
He came back from the toilet picked up his leather wallet then said "wish me luck"
To me it was a laugh but for some unexplicable reason he didn't see the funny side

, within 10 minutes he was back with a face like thunder and looking to kill some cnut, I must have pissed about 2 gallons in my pants laughing at him and the other lads couldn't stand up through laughing.
Needless to say it brought back down to earth a peg or two.