Dan Osman was a nut case. Another guy who died doing stuff like that was Michael Reardon. They call it soloing when you climb without a rope.
Osman died doing a huge swing off of one of the Yosemite faces when he hit a tree. He put a big line over a canyon, then climbed out to the middle and swung off. Theres videos of him taking a razorblade to the rope too before he did some of them for the adrenaline rush.
Reardon died when he was soloing a sea cliff and a wave came and swept him off.
Not saying they were bad people, they just have that adrenaline addiction that makes them do crazy shit.
On a sexier note, heres a little documentary on Steph Davis climbing without a rope.: