M&M Activity: Pass around a bag of M&Ms and tell the ambassadors to grab a small handful. For each M&M of a specific color, they must tell you something about themselves. For example, for each red, they must tell you a favorite food, green, favorite movie or TV show, yellow, interesting facts about themselves, etc.
Cross the Line- Put down a piece tape on the floor as your "line." Read statements out loud and if they agree, they cross the line. You can keep it light like "Cross the line if you've read all the Harry Potter books" or get deeper like "Cross the line if you've ever been bullied."
The Hot Seat: Have one ambassador sit in a chair in the middle of the room and have the rest of the ambassadors rapid fire questions at the ambassador in the center of the room. This gives the ambassadors a chance to get to know each other.