I’m not a fan of 37signals, but I must admit their DNS service is handy. I’m setting up some web servers right now, and I needed a domain to test my configuration. The whole DNS dance is a bit time-consuming: add record to zone file, & wait for my DNS to pick it up. With there’s no need to wait: prepend your host’s IP address before and the domain will resolve to your own IP.

For example will resolve to

They are other services like this like or, but as far as I know they don’t work out of the box: you have to register your subdomain first or can only use it with localhost.