Nerd for Maps

I'm a complete nerd for maps. I was trying to figure out the altitude of my house (to calibrate the altimeter on my watch, of course). I stumbled upon TopoZone. They have USGS topgraphic maps of various scales online! It's interesting to see, but they don't seem terribly printable. Since they're trying to sell paper copies of these maps, I understand.

I used to have USGS maps of the areas around my house and other places that I often found myself (Boy Scout camps, etc). I know how to use the maps with the compass and all that stuff, so it could be useful/fun to have when biking.

Armed with the digital compass on my watch, and a new mobile phone which can access and display these online maps, I could be unstoppable...as long as my batteries last, anyway! ;)