TV Nets Hope Games Will Hook Viewers

TV networks are using scavenger hunt-style games to attract viewers to their shows. Hundreds of players searched for clues online and offline, including on billboards in San Francisco and Minnesota, to crack a game linked to the CBS show "Numb3rs" last month. The network plans to promote more shows with games and hopes to sign up sponsoring advertisers.

CBS is also running a game for its show, "Jericho," and ABC operated a "Lost"-affiliated game. The efforts come with challenges, though: they're expensive to produce and it can be hard to roll out clues fast enough. During the "Lost" game, players solved clues faster than expected and were left "just kind of hanging around and waiting," said one participant.