Handling prank calls

I have just now had the pleasure of being the victim of a prank call. I was sitting comfortably in my couch, watching a movie (Gladiator) on maximum volume, while eating some of the best food I've made for a long while, when my cellphone rings. The display on it revealed the caller as using a hidden number, nevertheless I answered. I was met by silence at first. Then I could hear some incomprehensible voices in the background, there was the sound of somebody scratching the microphone in the other end and at a point the caller pressed some keys on his phone. Wow, I wish I was able to think up fun pranks like that. I didn't really have the patience to wait and see when the fun would end, so I figured I could turn the prank in my favour. I put the phone down and went back to watching the movie again. Apparently it took the caller a couple of minutes to realize, that the sound of swords against armours and from my fork against my plate was a clear indication that I was not listening. He hung up, didn't call me back.