Sometimes I enjoy tweaking the window washing spout on my truck so that it sprays directly over my cab and hits the car behind me.
I enjoy this. Sometimes I let the distance between the car in front of me to reach a hundred car lengths when everyone is bumper to bumper in grid lock. Then when the guy/gal behind me starts veering to the left and gesturing I hit the fluids...hehe delicious.
When I was a teenager we'd run the line to the front grills and squirt people passing in front of us. Or you'd get a friend who didn't know anything about cars to check a "pressure line" by blowing on it while you hit the "release"...yeah, instant mouth full of windshield washing fluid.
Another good one (if you had a theater with a balcony) was to find a film that had a queasy scene in it and sneak in a can of chicken noodle soup, wait to the gross part then make a retching noise and hurl part of the contents below.
You had to be a good sprinter for that last one.
Once a friend of mine put soup in a hot water bottle and did the sleeve/throw up gag into a salad bowl at Pizza Hut then had a couple of accomplices sitting with him with spoons instantly dig in.
That one got people banned from the Hut...or so I hear.

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