Distance: 3 miles

Obstacles: 12

Difficulty: The largest obstacle race in the world, Warrior Dash is a timed, competitive run. Still, most participants manage the muddy trails, minor hills, cargo nets, and slides with relative ease. Crowding at the events can be a problem, unless you're in the first, more ambitious wave.

The Vibe: For athletes looking for a fun, social event that still offers the we-just-survived-a-war camaraderie of completing a challenge. Generally all smiles at the finish lines.

Cost: $40–$60; warriordash.com