It's all about choices, starting with which entrance you choose. Down the pitch black, metal-walled tunnel, like boarding an airliner OF DEATH, feel your way along the walls, and into the exhibition hall.
Here you find the Pill Clock, which I'd read about when the exhibition opened: a heap of red-and-white capsules, added to every few seconds when a new pill drops from the ceiling (the attendant told us the dropping mechanism wasn't working today). If you wish, you can take one with a swig of water from the nearby fountain.
Once you've taken your pill you'll see a giant pink insect climbing a wall and a pair of free-roaming beds, which makes you wonder whether 'gelatin, placebo' was really an accurate description of the contents. Later it's rubber snakes, giant dice, and identical twins facing each other on two rows of monitors.
The interactive element is the most fun. You can put on goggles that make you see upside-down, and stagger around on the roof until you feel slightly sick. Then there's the flying machine, which we thought well worth a lengthy queue. It's a rig rather like a hang glider; you put on a harness and helmet, an attendant clips you in and starts the motor, and there you are orbiting six metres off the ground, waving to the pedestrians on Waterloo Bridge (who don't wave back, the miserable gits).
Exit was via the giant slides. And then the gift shop. (I had left my wallet in a storage locker, along with all other loose items, as instructed, so that was poor planning on their part, but Yag was kind enough to spot me £2 for a bookmark.)
I kept thinking how much callmemadam would have hated it all :)