I once had a girl respond to homecoming by placing an alarm clock under my bed and having it go off at 3AM. Attached was a sign that said yes. It's very disorienting to have an alarm clock go off in the middle of the night, trying to turn off your own alarm clock, only to realize that it's not the clock going off.

I also had a girl respond to prom by making a giant sign taped to our porch that said "PROM? there's NO WAY I'd say no". Only "there's" and "I'd say no" were written in tiny letters so from the street it just looked like it said "PROM? NO WAY!" We had ladies in our neighborhood who got super upset on my behalf about it because they thought someone had turned me down.