Have you seen this? Jon Petersen, of Playing at the World fame, dug up the demo tape for a short, semi-actual play session that was recorded way back in the earliest days of D&D. It's not really a podcast - such a term hadn't even been invented yet - but more of a radio play slash gaming session. That description doesn't do it justice; it is a heavily produced and edited radio play that clearly is taken from an actual play session. Some of the things the characters do could only have been done by actual players sitting at a table doing exactly the sort of things that make a DM wonder if they are serious or if they are just messing with him.
It's short, less than a half-hour, and the quality isn't great, but it's well worth a listen for anyone who enjoyed the old Dungeons and Dragons cartoon.