No one has ever managed to stay awake for much longer than about 10 days. Any longer and they keel over, strongly suggesting that a good kip brings real biological benefit. We simply cannot do without sleep. It is not just an evolutionary knockout drop. On the other hand, these experiments indicate it is possible to stay awake long enough at least to watch a Test match. The record for sleeplessness - held by 17-year-old American Randy Gardner - is 11 days, a feat achieved only by taking lots of cold showers, going for runs and playing games such as pinball. It is only after several days that problems start for people in such experiments: panics, delusions, voices, hideous mental images, memories of Steve Harmison's bowling, that sort of thing.