Egg shackling is very likely a relic of an ancient fertility ceremony.
It takes place every Shrove Tuesday in only two places in the UK; Shepton Beauchamp and Stoke St. Gregory, Somerset.
In the morning each child writes their name on an egg which they then take to school. The eggs are placed in a large sieve or riddle and shaken gently – shackled. As each one cracks or breaks it’s removed, until one egg remains. This happens on a classroom by classroom basis and each winner is given a small cash prize.
Here is a video of the egg shackling in Shepton Beauchamp in 2008.