Just a couple of examples on websockets in nginx-perl:
https://github.com/zzzcpan/nginx-perl/tree/master/eg/websockets/lib/Websockets
Draw.pm - multiplayer drawing thingy
Echo.pm - echo server
Demo (works only in chrome and firefox 11):
zzz.org.ua:55555/echo/
zzz.org.ua:55555/draw/