Taking advantage of the DNS protocol and TXT records for free, distributed caching (or just a cool hack, depending on your point of view).
I'm the main author of CGI:IRC, which was among one of the first 'Comet' based applications. It's looking a little dated now and could do with some attention, which I never quite find the time for. More..
Displays a summary of Wikipedia entries as title of links to Wikipedia. More..