Have you ever been traveling, and seen a building, landmark or other feature, and asked yourself - "what is that"?
I did, and envisioned a website that allowed a person to trace out that feature on top of Google Maps, and allow the Community to identify what it is.
Well, I was just talking to a colleague about Mumbai, and he proceeded to access WikiMapia to show various features of that city.
Turns out that wikimapia is fairly close to what I imagined. Google Maps, with the ability for the Community to mark geographic features. I think that a feature of the site called "identif this feature" would be useful. That way, a user could trace out something that they wanted to be identified, and another user could then do the identification.
Whatever comes to mind, and then the interesting directions that thought will take you on the web.