This is the "new" fad amongst married couples who like to hook up with other people. It was very popular in the 70s and has come back around in the last few years. Every couple who comes to the Fishbowl Party puts their keys in a bowl. Whomever picks your keys out of the fishbowl is who you go home with. Girls may come alone, but it is "risky". It's actually a very good way to lead your relationship toward a break-up and/or divorce.
If you are married and want to hook up with someone other than your spouse head to a fishbowl party and bring your spouse or hold one at your house!