I don't get too many calls anymore, but I used to put the phone down in front of the TV or the radio.
If I happened to be in front of my computer with iTunes turned on, my favorite was to turn to the Metallica song "So What", which starts out with "So F***ing What". I'd let them start into their pitch, I'd put the phone in front of the speakers then let that song play all the way thru. They were always gone by the time the song was done.
