It's not really all that close to what kind of device it sounds like it could be, but the Telecrapper 2000 (TC2K)
may be as vindicating and satisfying experience as we can imagine. Do Not Call Registry be damned, the TC2K identifies
incoming telemarketer calls and using caller ID (or more specifically, their lack thereof), and is programmed to
ensnare the caller in a software-driven conversation in order to keep them on the line as long as possible—the theory
is that by decreasing their overall productivity, and telemarketing becomes an undesirable business proposition. But
for your trouble you get something out of the deal, too—a tidy recording of the "conversation," which we might call
both painful and hilarious.
P.S. You may just want to peep this flash rendition of a recording.