Watching Ridiculusmus's sketch show is an unsettling experience. Wearing rumpled suits and slightly pained frowns, the duo - Jon Hough and David Woods - simply stand side by side, swapping, sometimes mid-sentence, between a series of odd characters. We meet Brendan and Pat, scabrous Irishmen with dodgy pasts, Mrs Mumtford, desperately searching for someone to cut her 92-year-old grandmother's toenails, Jackie and Gina, screechy housewives with a penchant for birdseed. These characters are gradually eliminated from the show, until we're left with just Dave and John, versions of the duo's real selves scathingly dismissed as "good-for-nothing wanky artist types", who shrivel before the microphone because they can't stand the sound of their own voices.
This is humour for people who prefer their comedy dark, edgy and strange. A lot of the sketches would have fitted perfectly into Chris Morris's Blue Jam; you gasp more than you laugh. Not that the duo aren't capable of delivering direct laughs: Pat's unexpected John Hurt impression is hilarious, as are the savage parodies of Late Junction and Desert Island Discs. They are glimpses of light in an hour of nightmares.
· Until August 25. Box office: 0131-556 6550.
