1-Forgo the sports bra and wear a speedo or tight fitting swim suit. This will make it easier to wash mud off you in a public shower. It's easier to rinse off in a swim suit than a sports bra and shorts!
2- Tank tops only! I just ran in pelting rain and a not so balmy 58 degrees. It was cold but a wet t-shirt will weigh you down.
3-Do not wear your good workout gear! It will get stained and ripped in the course. Not worth it!
4-Wear a pair of tight fitting shorts or leggings. You will be banging your knees on rocks and obstacles. Be prepared for bruises, cuts or wear something to cover your knees!
5-Opting for shorts? Wear some tall socks to cover your knees and protect your shins! Bonus if they can cover your knees for crawling obtacles!
6- Wear sneakers you are willing to part with! They will get wet and be destroyed when you get done. Be prepared to donate them or make them yard shoes when you get home
7-If you are going for time avoid the costumes. They will get snagged on obstacles. Admire from afar!
8-Leave your jewelry at home. No rings, earrings and definitely no necklaces. They will get dirty and possible snagged on the course!
9-Arrive early! Parking can be a nightmare at the novelty events! Get there early, pick up your packet and bib, tailgate as neccasary!
10-Throw your modesty/pride out the door. Be prepared to ask for help on obstacles and have complete strangers assist you through the race.
Hope this helps your racing experience! Have you ran an obstacle race before? What did you wear?