DIYer Nicholas combined a USB Propeller and an Ethernet module (which ran him about $US12) to make a mini web server with an IR circuit. With it and a bit of simple code, he can send IR signals to any device from a web browser window. It's not something everyone necessarily has a use for, but has quite a few possibilities in the realm of home automation. Check out the video for a quick demo, and hit the link for full instructions.
Control Your TV with Your Phone [Instructables]