Trevor Squires, he of the neat Ack bundle for TextMate, has released his most excellent Campfire chat client: Propane. Now at v0.9 (but rock solid for me for some weeks) it's available for a limited time for $20. I just snagged license number 197.
It's a nice, focused, app that adds value to campfire and delivers all the nice stuff i've had from various different routes to campfire in one app. Well worth it to me. If you've ever used Campfire I recommend giving Propane a try.