Ragnar Relay Named for a 9th century Norse king and pirate, this annual 24-hour race stretches a grueling 195 miles from Valley of Fire State Park to the Red Rock Resort. Teams of 12 runners divide the distance, with each competitor taking three legs staggered over the course of the day. You can sleep when you’re dead, right? October 22-23, ragnarrelay.com.

Running with the Devil Marathon For the truly psychotic, there’s Running with the Devil. The aptly named annual race simulates a competition from hell by hosting it in the middle of the day, in the middle of the summer, in the middle of the Mojave Desert. Crazy? Yes. Suicidal? Maybe. Just remember: Pain is temporary; bragging rights last a lifetime. June 25, 2011 (tentative date), 50-miles, marathon, half-marathon, 10- or 5-kilometer distances, calicoracing.squarespace.com.

Tough Mudder Think you’re tough? Think again. This seven-mile obstacle course on steroids is designed to find your only weakness and exploit it. Done in teams prone to dressing like characters from Braveheart, the race includes about 17 challenges, like wriggling through tire tunnels, struggling through waist-high mud and running through fiery piles of kerosene-soaked straw. Southern California, May 28-29, 2011; Phoenix, Dates TBD, toughmudder.com.