OK, so my last question turned out to be a bit stoopid. Lets draw a veil over that.
In trying to find the (obvious) answer via Google, I discovered that amongst the people selling their London Marathon medals on eBay, there are people selling their timing chips. Not only that, but one even has a bidder.
Now I can see how someone might lose their medal in the pub on Sunday night and how others may want to make a few more quid for their charity by passing theirs on.
But who wants a timing chip! Is it just memorabilia gone mad? I've still got mine on my shoe. When I can look at them again without wincing I'll be chucking the chip away. Maybe I should have it mounted instead.