None of my students won at the invention convention but I give them an A+ for effort. Especially the inventors of the "Party Bus."
I've implemented a reward system that gives groups of students points each day if they (mostly) don't behave like rabid hamsters. The "Dolphins" were the first to reach 20 tallies and get their pizza.
And the daily comedy of teaching fourth graders...including improvising really stupid stories to serve as models. And probably misspelling "Sqwuack!" but being happy that it's on the board, nonetheless.
And when you find a secret, hidden note from a student who you thought despised you.