If you work in an office get a wireless mouse and plug it in to your victim's computer then randomly move the mouse to drive them insane.
I used to be a mechanic at one dealership we would give lot techs a 5 gallon bucket and send the to napa for a bucket of steam for the steam cleaner.
LOL. I used to be a tech many years ago, myself. I wired a new guy's horn to the hot lead on his starter solenoid while he was at lunch with another guy in the shop. We also put extra, old lug nuts we had sitting around in his hubcaps.
cellophane stretched tight across a toilet bowl is always good, just do it at work or someplace other than your own house
1) Go to your wife's computer when she's not looking.
2) Take a screen print of the desktop background, with all the icons.
3) Copy it into Paint, and save the picture as a jpg.
4) Create a new folder, move all the desktop icons into it.
5) Hide the folder.
6) Change the background image to the jpg you saved.
7) Enjoy.
Once, I had a brownie that I rolled in my hand in the shape of a turd (about a small dog sized). I walked up to a friend and acted like I picked it up off the ground. He was like, WTH man put that down. I smelled it with a look of disgust on my face, then proceeded to eat it. I said,
"It sure tastes better than it smells"
I think he about threw up.