What is my IP address?
It's often useful to be able to find out what your external IP address is. I often check when I'm at client sites, to discover if I'm behind a NAT, remind myself whether I'm browsing through an SSH tunnel, and so on. There are a number of sites available that provide this service, e.g. whatismyip.com and myip.dk, but I recently decided to set one up on Kitserve. It's accessible at https://secure.kitserve.org.uk/ip/.