The Hotel, Assembly Rooms @ George Street, Edinburgh

If, like me, you've ever wondered what stand-up comedians do to while away the long hours of daylight before they take to the stage for their late-night hour of work, wonder no longer. They're all moonlighting as bell-boys and receptionists in the worst hotel in Edinburgh.

Set to be one of the must-see happenings of this year's Fringe, The Hotel is the brainchild of the comedian Mark Watson, a perennial over-achiever at Edinburgh who has previously performed 24-hour shows and written a novel over the course of his run in the city. Now, he's brought together some of the finest young talents around to take part in a part-promenade theatre, part-art installation, part-improvisation show, set in a fictional hotel.

Watson himself plays a frantic inspector rushing from room to room to record the horrors while a rotating cast of up-and-coming comedians play the staff. You might be given a (mildly intrusive) personal training session by Mike Wozniak in the "Wellness Suite", served your lunch by Idiots of Ants or serenaded by Alexis Dubus or Tom Basden in the basement cabaret bar.

Having collected your tickets at the Assembly Rooms, you are led down the street to an unassuming townhouse. This is The Hotel, winner of the Highly Commended for Best Integration of TV in Lounge or Games Room Award. And that's about all there is to recommend the establishment. Inside is a hospitality disaster far outstripping anything Basil Fawlty might have imagined: a business centre where the computers are all hard-wired to show only porn; a restaurant that serves cornflakes for lunch and cream crackers for dinner; and a massage room which also serves as a general thoroughfare.

The audience is invited to wander around the floors at will, perhaps participating in a little zen meditation with the resident "guru" in the chill-out room or stumbling across a sweat-soaked job interview in the boardroom.

By far the best experiences come when you break off from the crowds and explore the sinister set-up for yourself. On the day I "visited" there were far too many people being herded from room to room, which interrupted the flow of the more rehearsed scenes, and some of the improvised interactions with the staff feel a little underplayed at present.

Still it's an intriguing and exciting way to spend an hour. Best of all are the fine and lightly insane touches of Becs Andrews' detailed design, from the pictures of guests "yet to visit" on the walls (Helen Mirren, JFK...) to a stunning lost property cubbyhole. Don't be afraid to open all the doors and poke around in every cupboard; you're a guest, after all.

To 31 Aug, not 17 (0131-623 3030)