OpenSSH 4.3 was released today. I've been eagerly anticipating the new feature; here's the description from the release announcement:
Add support for tunneling arbitrary network packets over a connection between an OpenSSH client and server via tun(4) virtual network interfaces. This allows the use of OpenSSH (4.3+) to create a true VPN between the client and server providing real network connectivity at layer 2 or 3. This feature is experimental and is currently supported on OpenBSD, Linux, NetBSD (IPv4 only) and FreeBSD.
Being able to easily make a VPN which can take advantage of SSH's authentication subsystem is a big win if you ask me.