This is the result of a £28 (~$43) Happy Ride Vibrating Bike Seat (links to NSFW adult toy website). The seat cover vibrates against your privates while you ride, making exercising way more enjoyable. You know, it's a shame God didn't make exercising feel better on your privates, then maybe I wouldn't be such a rollie pollie. "He did -- it's called sex." Oh right, in that case I'm super fit. I have so much sex I have to keep it in Hefty bags.
Thanks to Marc, who informed me you haven't lived until you've been hit by a bus while orgasming.