At PC Forum 2006, one of the coolest new services I saw was Spot Runner, a company that aggregates unsold television ad spots and resells them to small, local businesses. Apparently it costs much, much less than you might think to buy a prime-time ad on a cable channel, such as the Outdoor Life Network, or even CNN: as little as $18 a spot. (Except in Manhattan, Spot Runner CEO Nick Grouf says.)
Since the cost of television advertising also includes the production of the content itself, and since that can be prohibitively expensive, Spot Runner also has generic video ad templates that customers can use.
There's a full write-up on News.com.