It's Third evening chez Framescourer which basically means trawling the interweb for live, alternative and video-amalgamated performances of the album. Here's their official You Tube site which, charcteristically, isn't terribly helpful (at first glance) and their MySpace page for the Third which is little better.
Bring on the fans.
This dude has a library's worth of material (i.e. his account is minutes away from suspension, I fear) including live performance sessions on Radios 1 & 2 and Jools Holland's show, a number of Current TV videos (Portishead's version of Radiohead's Scotch Mist series of studioy videos) and videos from the special edition of the album. One of the latter is a nightmarish, free-flowing animation video by Nick Uff (who also created the video for The Rip) which looks like this: