Tough mudder is $150 (early entry) and they had over 20,000 entries during 2 days in NJ two years ago - nice haul!
And I though spending $35 on a 0:45-1:15 bike race was expensive. I guess you are also paying for the extended expenses involved with the race infrastructure (or lack there of?). I was also pretty mind blown to learn that 5K's cost about as much as the bike races I do.
FUN FACT:
Everyone who ran last weekend got a medal.
*confetti*