I'm pretty sure that I'd buy a T-shirt to support this event
Maybe something simple. Or with blue CSU kernels on the cob?
I really like the OUSA + corn kernel graphic at the website...
Before you go printing a bunch of these shirts, you might want to get permission from Orienteering USA about logo usage, and whether or not it conforms to the style guide* of logo/wordmark usage.
* which doesn't exist yet officially, but I'm working on it.