Trolley-spotting in Nottingham!

This morning I wrote about MyWalks - a project to get people engaging with their environment... Someone who's already doing that, by the looks of things, is Adele Prince - the London-based artist (and closet geographer, I think!) behind Trolley Spotting (thanks to Ollie Bray for highlighting this site).

Armed with a GPS and camera, Adele went trolley-spotting in Nottingham, London and Portsmouth, and has mapped the locations of the abandoned trolleys she spotted, as well as other interesting discarded objects.

What else could be mapped in this way? How about starting your own equivalent of the trolley-spotting project?!