I've added a very fun new feature on Crosstips called Crossing the world which shows real-time searches happening all over the world. Admittedly the traffic on Crosstips isn't particularly high, (At the time of writing, 1 search every 2 minutes) so you might have to sit there for a while until something happens. It's strangely addictive to watch it.
To do this I had to use all sorts of buzz words. AJAX, function cache decorators, GeoIP and Google Maps. I'm currently using the free version of GeoIP City Lite which seems to work on a large majority of all captured IP addresses. And since the map is sufficiently zoomed out you can't really tell how inaccurate it is.
One little detail I'm quite proud of is how the AJAX code understands how to change interval between lookups. Each time the server responds with something, the interval is reduced down but if there aren't any new searches the interval slowly increases again. This is done to minimize the number of useless server requests but at the same time try to make it react often if there are plenty of things to show. The next feature to add is Comet (like AJAX but push instead of pull).
Now if we could only get some more action on the site!! Tell all your grand-people to use this site when they get stuck on solving crossword puzzles!
I've just learnt that GeoIP is already shipped in GeoDjango so I've basically reinvented half a wheel :(