The Radio 4 programme Material World is sponsoring some research into homing instincts of snails. As part of this, they are looking for people willing to swap snails with their friends - you both collect snails from your garden, dab different coloured paint on to their shells, swap snails, release your friend's snails in your garden, then wait to see if your snails, released in their garden (and identifiable by different paint colour on shell) find their way back to your garden.

Click on 'The great Snail swap' link at the bottom of this page:
BBC - BBC Radio 4 Programmes - Material World, 01/07/2010