This summer, Bob and Erik Petersen will drive from London to Ulaanbaatar, Mongolia in a 1993 two-door Ford Fiesta with a 1.1-litre engine. The family has a history of mental illness.

Bob and Erik are attempting this journey in such an obviously stupid way because they are taking part in the Mongol Rally, the rally that's not so much about winning as it is about seeing how dumbfoundingly difficult you can make things on yourself for no good reason. Hence the main rally rule: every car must be at least 10 years old, and no car may have an engine larger than 1 litre.

Every rally team must raise £1000 (about $2,000) for charity, plus an extra £100 for every 0.1 litre over the 1 litre limit. Therefore the Petersens' luxuriant extra 0.1 litre pushes the total up to £1100. Of that, £500 goes to the Christina Noble Children's Foundation. Ulaanbaatar has a large population of street children, many of whom sleep underground in the city's sewers for warmth during the brutal winters. This excellent organisation exists to help them.  

(The other £600 goes to MercyCorps, the rally's primary charity. See our other page, www.justgiving.com/mongolbob, for info on that.)