I like to play beach volleyball in the South Bay (Los Angeles). One of my groups has the issue of having a different number of people come out every week and we need a fair way to create random teams. A slight complication is that some people only want to play doubles games (teams of 2 people) and some people only want to play group games. Some people don't want to play in large group games (5 or more people on a team), including myself. So those types of preferences/quirks were considered in the options of the app. This is a link to a blog post with additional info: http://spikeandsand.wordpress.com/2013/08/13/app-for-creating-volleyball-teams/
A live version of the app is at: www.carolchung.com/vb