You have some very strange friends Ozzy. This definately is one of thoes Only in England things. Don't they do a cheese wheel race there too? Someplace up north I think. Saw that one on the news.
I don't know about cheese wheels but they roll cheeses in various places.
5th May
Stilton Cheese Rolling, Stilton, Peterborough
A cheese-rolling championship and May Day celebrations
Spring Bank Holiday Monday
Cheese Rolling, Cooper's Hill, Brookworth
They used to roll painted Easter eggs down a big hill somewhere for the children to chase. This might have been banned in recent years due to health & safety regulations. Too risky now in case someone gets sued.

We've always been a tad eccentric on this side of the pond. I remember a traditional tug of war across a river on the Norfolk Broads. The losers end up in the river before they all celebrate at the nearby pub.. These things nearly always end up in the pub.
Here's a few more bizarre British customs.
http://www.woodlands-junior.kent.sch.uk/customs/curious/index.htmThey don't mention the World Marbles Championships at Tinsley Green, near Gatwick Airport which is now a truly international event.
http://www.marblemuseum.org/tinsley/players.htmlThe German teams keep winning now. They're a tad eccentric too.
