Rob Brydon had a short-lived series called Directors Commentary that aired briefly in the London region back in 2004 and is now doing well, surprisingly enough, on DVD. In it, he pretends to be the original director of TV shows such as Flambards, Bonanza and The Bounder, dishing out completely made up facts and horrendous prejudice along the way.

Adam Buxton's also got in on the act with his own fake commentaries using the character of Ken Korda. Korda is due to appear on the DVD of The IT Crowd narrating a spoof behind-the-scenes documentary about the show. He's also appeared on Charlie Brooker's Screen Wipe doing fake commentaries for The Mint:

These commentaries have one thing in common: the narrator pretends to be the director. But alternative commentaries have been around for far longer. There's the joy of The Rocky Horror Picture Show's audience commentary, for example.

Doctor Who fans are getting in on the act with their own podcast alternative commentaries, such as those offered by Tachyon TV.

Then there was Mystery Science Theater 3000, which had a group of robots and a solitary human watching rubbish science fiction movies and adding their own commentaries to the proceedings:

The star of later seasons of MST3K was Mike Nelson. He's now launched his own web site, RiffTrax, dedicated to alternative directors' commentaries. He's also trying to make money from them, since he charges $1.99 per RiffTrax.

I'm not sure I'd pay $1.99 for a fake commentary, particularly if I can't hear a sample, but it's an interesting experiment. Will this kind of commercial alternative commentary pan out? If it's good, it surely will.

But how much of an audience base is there, I wonder. How many people listen to the real commentaries? What do you think?