We've done one during a football game - it was a sponsorship. Got run every quarter and then our name was mentioned as a sponsor I think 6 times. Not one single call but I cannot tell you how unbelievably COOL it is to hear a professional commercial done about YOUR company - it was so neat!!
We did one early on. A local DJ bartered with us for a few plugs during the morning show. We wound up doing the DJ's house and thats all that became of that..