Now that's small.
Just ran into this article on LinuxDevices.com. It talks about a tiny computer that looks like this:
all there is to it. This ethernet jack has an ARM9 processor in it with
8 MB RAM, 4 MB Flash, and some interfaces that you can hook up
electronic devices to. The idea is to add network connectivity to
devices that normally don't, like air conditioners and stuff.
Apparently there's even a WiFi version of the thing.