I've been watching the Olympics and have been inspired a bit. So here's the breakdown.

Draw your OC either doing one of the Olympic sports, in one of the uniforms (either your country or the country they are from, gymnastics, swimming and triathlon outfits are obviously included too), or being a cheerleader for your/their country.

OR

Draw your OC in a uniform for a professional team you root for or they like, and also the cheerleader things apply there too.