The location for Sat May 31 was certainly an interesting one (and within 10mn of my house). There was a police kennel facility right on the shore of the Mississippi river between the road and "the spot". I'm pretty familiar with the area though so I gave it a shot.
I took as my legal principal the idea that as long as I was still out side the fenced area I was ok, and tried to see how close I could get. Turns out it was possible.
The background music is a couple of cues from the 80s animated film The Brave Little Toaster.
Here is the location: http://irc.peeron.com/xkcd/map/map.html?date=2008-05-31&lat=45&long=-94&zoom=7&abs=1
For info on geohashing, go here: http://wiki.xkcd.com/geohashing/Main_Page