If crowd-surfing was an Olympic sport, 18-time gold medalist Michael Phelps wouldn't even make the podium.

Phelps is adjusting to life after swimming with some new ventures. First there was golf — at which he is apparently a natural — but his latest adventure left him on the floor, and presumably with a sore back.

A video from Phelps' recent excursion to Las Vegas shows Phelps and a female companion boarding a raft together, assuming the crowd would support them and send them on a nice easy ride. Phelps' co-pilot rode comfortably with the help of the club's crowd, but Phelps was left out to dry.

Check out the video below to see Phelps' Vegas tumble.

Michael Phelps Takes Hard Fall While Crowd-Surfing on Raft in Las Vegas (Video)

Video via TMZ