Vonage users can dial 1-700-CALL-SANTA to hear a recorded message from Santa Claus (and leave him a message). It's mostly appropriate for kids, who probably won't even notice the carolers singing "Use a Vonage Phone!"
A nice surprise: After your kid leaves a message, the recording is e-mailed to you. A sneaky way to find out what someone wants for Christmas, or eavesdrop on the nasty things they said to Santa.
(This number doesn't work from non-Vonage phones.)