I like how on GTalk you can set yourself to do-not-disturb or available; however, I'm always forgetting to set the appropriate status. As such, I got my faithful desktop to set my availablity on a timer.
In true fashion of being a geek, I have combined technologies help me out. This time, I strung together GTalk, XMPPPY, and cron to engage in some silliness. The fun bit was that it wasn't hard. A snippet of code, a quick install of xmpppy via apt-get and some time spent wrestling with cron.
I imagine, in the future, I'll be setting countdown status messages, perhaps nagging myself via IM, who knows?