GroupFly is a free app that lets you set-up temporary social networks to meet new people, organize events, promote a cause, or just have fun. Every GroupFly network has a Disband Date, after which the network dissolves. You can always convene the same GroupFly network again if you like.
Search the universe of existing GroupFly networks and join one (or more) of them, or create your own. GroupFly networks can be private, where participation is by invitation only. Or they can be public, where anyone can participate -- allowing you to meet and interact with new people without the pressure of a permanent connection.