People at my high school got all creative with that stuff... it was a pain in the ass.
For senior prom, I ended up having the principal deliver my date a package with a cell phone in it while she was in class, and then when she opened it i called it and asked her like that scene in the matrix where he gets the phone... except she hadn't seen the matrix, so she didn't get it.
For my junior prom, me and my date were going with my friend and his, and me and my friend showed up in $10 value village suits with mud smeared all over them and were like "uhhh we fell down" and then we gave them corsages that were each an entire corn on the cob. It was classy.
If people at your school aren't into the overdone creative shit though, you should probably just straight up say it.