Shows live user statistics from OpenStreetMap.
Or try it out on the live server (note, uses port 8080 so be aware of firewall issues).
There's a server component written in Perl (this was meant to be rapid prototype for something I'd later do in C++ but then proved totally sufficient as-is). The server loads minutely diffs from OSM and parses them, and for each minute keeps a hash with user names and associated edit counts. (The server doesn't currently discard anything so it'll fill up your RAM after a couple of months... or years.)
For convenience, the server acts as a web server and delivers the index page and JS/CSS files needed by the front end (see below), though this is really just a gimmick.
There server has a JSON API where you can basically ask for a list of users and edit counts for any time span, and what you get back is a JSON array with user names and edit counts.
Then there's a small front-end made with JQuery and Flot that will show a nice bar chart with user edits. The front-end interpolates between two subsequent minutely diffs so that you see "something moving". Of course it's cheating a bit (in a "show me the way" kind of fashion).
Once you've got one or two additional Perl modules installed, you should be
able to simple do perl daemon.pl and then connect to localhost:8080 with
your web browser.
If you don't want to run the server yourself, you can build something on top of the API of the live server on www.gryph.de:8080 but that server is really just for playing and there's zero service level guarantee (and the API could change any time).
Everying is PD except the Flot and JQuery libraries in the "js" directory which come under their respective licenses, see the .js files.