This was my suggestion for QOTW i think it'd be fucking ace!
I've had a few really good ones a brief summary of which, is below;

Buy a pack of smoked kippers. Place one under someone's bed to be 'found' later. Then, remove the vent cover from the chimney brest wall and place the other kipper behind it. Replace cover. 6 months down the line, explain why their room STILL smells of fish even though they removed the kipper from under their bed some time ago...

House mate in bed, cling film the outside of his (inwardly opening) door. Shout that there's something urgent (i.e fire) and make him leave his room in a panic without his glasses on.

Same housemate, on holiday for a week. Bought all the tinfoil we could find and redecorated his room. 'Wallpapered' it, wrapped all his furniture, wrapped everything on his desk individually, tinfoil curtains, literally everything. Replace bulb for a 150watter.

Same housemate, turn everything in room upside down. Bed, Wardrobe, desk, CD player - the lot. Laugh as he only notices after ejecting a CD and having it fall on the floor.
(Colonel Santiago Introduced surprised kitty to the world., Fri 5 Mar 2010, 16:03, 2 replies, latest was 16 years ago)

when she's not looking I'm going to put super glue all over her beer can

( Lisette von Falcon, Fri 5 Mar 2010, 16:08, Reply)

Just rape her.
That ought to mess her up a bit.
(Colonel Santiago Introduced surprised kitty to the world., Fri 5 Mar 2010, 16:10, Reply)

done the clingfilming one
but we filled the space between with the contents of a big bean bag
( Vipros. clever got me this far, then tricky got me in, Fri 5 Mar 2010, 16:11, Reply)

Ha ha ha!!
Yes!
(Colonel Santiago Introduced surprised kitty to the world., Fri 5 Mar 2010, 16:12, Reply)