Do something dumb with notices.

[Arctem]

Maybe alert about the start of a game with them?

[Utanith]

Notices would probably be the preferred method for sending players their words in coerce and such; some clients display notices from users that you're in a channel with appear in that tab (Or window or w/e), which is convenient. In fact, I think you can multicast notices - So you could feasibly inform only the players and not the whole channel. This could be useful functionality for other games with secret information.