I take no credit for this idea, but it's tried and true and can be fun. Get into small groups and give teams five minutes to come up with 20 things that are unique to just one person in the group (for example, Cindy is the only one who has been to Paris). In round two, challenge the group to come up with 10 interesting things they have in common. Personal appearance should be excluded as options for the commonalities. Once a team has their list, challenge them to create a team name combining as many of the commonalities as possible (for example, one team might be the Cliff-Diving Chocolate-covered Ant Eating Lousy at Math Chess Masters Extraordinaire!). Invite each team to share their creative name with the group.