In the midst of re-designing SEOmoz I decided I really needed a change of pace. I've only lightly used AJAX, so I decided to build an AJAX powered tool that looks up the geographic location of an IP address. It seemed simple enough to build and I figured it'd be good practice for some upcoming SEO tools we've got in the works. The database I used to look up the location of the IP addresses provides the latitude and longitude of the targeted IP, so I threw google maps in the mix as well (GG maps accepts latitude and longitude for designation locations). The coordinates provided for each IP can be a bit weird (apparently the IP at my residence is in the middle of the mountains near north bend), but it's at least good for narrowing down the city, state, and country of the IP you're targeting.

Check it out if you have a chance: AJAX Powered IP Location Lookup.