From Rikki Unterbrink, Youth Services Director, Shelby County Libraries (look for her Pinterest pages!) Her teens love playing Humans vs. Zombies. They use balls of felt. One or two zombies, everyone else is human. The humans have nerf swords/guns and have to retrieve 5 items from around the library before they are turned into zombies.
Updated version could be Aliens vs. Humans and tie it to the Fifth Wave.