I love when you are looking around the far flung corners of the globe that you've traveled too and you see that there are high resolution Yahoo Images of the area. This means you can start tracing and getting some basic road layout of an area done.

I recently discovered that Dar Es Salaam in Tanzania (pop 2.5million) is almost completly unmapped but has high resolution Yahoo imagary available. :) Time to start tracing out some road networks!