It might be too late this winter for this (at least for those of us in warmer parts!) - but how about shots that depict how cold it is? Or, alternatively, in the warm months, shots that show how hot it is. And the twist it - no people allowed. Just use your imagination and creativity to get the message across.

And - expanding on the "where am I" idea - shots of everyday items at unusual angles or in macro and we have to guess what they are?