OK, we used flash, but it's still a cool use of asynchronous browser to web application communication.
We have just launched the new lottery Quicky (Not available between 00:00 am and 06:00 am CET) (I don't know whether it has the same meaning in english. In german it means fast, spontaenous sex; however the lottery it totally unrelated to sex. Somebody from the marketing department probably thaught it was funny).
The drawings are broadcast live on the internet every 3 minutes using a flash movie, that is also used for playing the lottery.
The flash movie talks to the server using an xml file, that contains drawing data and a time synchronization signal. The server itself is a super fast mod_perl handler that fetches the drawing data from a memory cache and assembles the xml data. The only calculation performed is the offset between client and server time.
The Lotto Jackpot survived yet another draw and it at 24 million now (which is basically a synonym for DDOS). We'll see how we manage the load.