Want to run insanely long distances in the midst of a Texas summer? Well, here's your race! The Habanero Hundred offers a 10k, 20k, 30k, 50k, a 100k and a 100 miler, plus a 100k and 100 mile 5-person relay option if you have four friends as crazy as you. The race kicks off at high noon and has a 30 hour cutoff time.
Organizers realize the dangers of running in such heat and have lots of advice for pre-race prep on their website. Plus, the loops are short, meaning you are always less than 3 miles from an aid station. You can ice up at each aid station and keep as cool as possible. The park has some decent cover so that you aren't always super exposed to the sun. The reason for an out and back is so that runners will always cross paths and will be able to encourage each other as the loops pile up.