I never competed in an Actual 5k or race and probably don't plan on doing so. There are many factors mainly having to wake up early.
I have this idea for a race called The Mario Kart 5k / 10k. Every person goes about it like a regular event but we put stuff on the course for people to use.
Example: a bucket full of water baloons to throw at people or giant soft teddy bears.
I've run more than 20 5ks, and that is the single best idea I have ever heard, though I'd hate to be the guy in the lead in one of those races