I've tried
chatroulette.com and some of the alternatives the past few days. Since chatroulette.com has been down for almost a week now, the clones are sprouting up like crazy. Many clones and alternatives have so little users that you're being connected to the same person over and over, or it fails to make a connections at all. In the end I found
omegle.com and
anochat.com the most useful. They're fast enough, especially anochat, and they have enough users to make wasting your time at least slightly fun.
What I don't understand though is what makes so many men take out their willies and start wanking behind a cam for the whole world to see. Just for fun I did a little experiment; I placed a mirror exactly so that chatters were able to see their own image when connecting with me. This provoked some funny results, from a simple "wow" to a girl from Greece showing her ass. She must have really enjoyed watching herself. Man, did she get my blood flowing :-)