I have a plan: Buy a cheap 2mp digital camera (between £20 - £40 ebay/morgan computers/etc eg this) ideally small, with flash. Setup a website (perhaps a blog?) where people can post their pictures taken with said camera. Camera is posted to people around the world, they have it for a week, take X amount of pics, and upload 5 of their best pictures to website (as pic above), then post it to next person in line. This would only work if people didn't decide to steal the camera - to combat this, perhaps I could use a paypal account to collect deposit (perhaps £5/£10) which is refunded once the camera has gone to the next person? The address list (so to speak), could be centrally managed by me. So it would go like this:

1. Email me, with your address. (and put deposit in my paypal account)
2. I'll invite you to join the blogger
3. (once joined) Someone will post camera to you.
4. You use for a week, upload 5 of your favourite pictures to website
5. Let me know you're done, and I'll email you the address of the next person.
6. You post the camera to the next person (when they confirm they have it, I will refund paypal deposit)

alternatively, they don't post their pictures, but they could just email the pictures (With text) to my email account? I could also mark the camera with something like "If found, return to (web address)".