There is an interesting new project called Varnish, which implements a reverse proxy. It is apparently up to 10 times faster than squid. But more interesting is why.
The software architect, who is usually a kernel programmer, decided to do a "userland program" for a change, as a fun project. Apparently he was disappointed that most programs haven't even taken advantage of things that have already been available in FreeBSD and Linux for at
least 10 years.