Use Mightyname to discover fun domains to register
MightyName displays a list of randomly assembled .com names that are available to register. The page can be refreshed to display a new list or you can use the search tool to enter a keyword to find more specific names. The combinations that it comes up with are quite amusing. Good for inspiration if you're stuck and can't find a domain for your random side project.
The best tool I've found so far for name brainstorming.