If you are looking for simple way to control your PC using your remote TV, this TinyPCRemote project by Nathan Chantrell is good solution for it. The project allows you to use infrared remote controls to trigger keyboard commands (single characters, string or Meta keys) on your PC. You can use it as media player remote control or make a joke by controlling your friend’s computer anonymously.
The project hardware consists of ATtiny85 and TSOP31238 IR sensor. It uses V-USB for USB implementation. The device doesn’t use IR protocol to detect remote button, but it detects ‘codes’ generated by pressed remote button. With this ‘codes’, you can define what keyboard commands that your want to issue on your pc.