Fog Creek was named so because of a small stream outside their former office that had a habit of being dense with fog. He talks about it in the StackOverflow (Episode 13) podcast.
What I would suggest is try to find some unique thing around you.. it doesn't necessarily have to make sense in terms of relating to your product. Being relatively short and memorable is a huge plus.
Here are some guidelines outlined in "7 Tips for Naming your Startup" that I find useful:
1. Keep Length at a Minimum
What's easier to type in multiple a times for day for a simple web search, Google.com or AskJeeves.com? It's clear why AskJeeves shortened their name to Ask. If you can't beat competition on quality and functionality, you'd better be aiming to make it as easy as possible for users to access your service. How easily a domain name is typed can make a big difference in whether or not a visitor will want to visit often. Part of the reason I read CNN.com for news is how easily the three letters can be typed into the address bar. A good length for one word names is five to six letters. Names should typically also never exceed two words.
2. Be Generic or Be Original
When Flickr exploded in popularity, quite a few entrepreneurs seemed to think that it set some sort of de facto standard for Web 2.0 naming conventions. It didn't. Naming your service Locatr, Bookmarkr, Zooomr, Preloadr, or Frappr doesn't put you next in line on the Yahoo acquisition queue. Either go for an expensive generic name that accurately describes what you're about, or be creative by choosing an effective and unique name that stands out.
3. Encourage Word of Mouth
Company names should not be difficult to pronounce or spell. If a name doesn't roll of the tongue, then choose something simpler. Can you imagine people around the world asking each other, "Have you heard of the web service PriceWaterhouseCoopers?" Well, neither can I. Once a name has gone from one person's mouth to another person's ear, there shouldn't be any confusion as to how its spelled when typed into a browser.
4. Capture the .com
When Nintendo revealed that their seventh-generation console would be named "Wii", the domain name Wii.com was already registered by someone else. Luckily for them, they had the money it took to acquire the domain from the existing owner. If your pockets aren't as deep as Nintendo's, think about working your name around to fit a .com instead of working domain extensions around to fit your name. Even if a domain is unavailable, look up the whois information on the domain and attempt to negotiate for it directly from the existing owner. Ever wonder how many extra hits Disney's dig.com gets because of the popularity of Digg? It would greatly benefit Digg if they got their hands on Dig.com, but I doubt Disney would sell now. This is also why thefacebook.com quickly purchased facebook.com from the existing owner when they had the money to do so.
5. Avoid Using Hyphens
Only in special circumstances do hyphens benefit a website (e.g. experts-exchange.com instead of expertsexchange.com), but in most cases they don't. Don't burden your startup with a hyphen in the domain name just because the hyphen-less domain was already registered. How do you tell some to go to a website if there's a hyphen in the name? If Myspace used the domain name my-space.com, how many people a day would erroneously type in myspace.com? There's a whole industry of people who specialize in profiting off typo domains. Don't feed them with your ignorance.
6. Avoid Domain Hacks
Yes, there was a time when it was creative and unique to name your service something like Del.icio.us, but now domain hacks have gone from being special to being inconvenient. That's probably why Yahoo acquired the domain name delicious.com as an alternative (and easier) way to access the service through the address bar. Words in the English language don't usually have multiple periods within them, therefore it takes more brainpower and time to type them in (both of which are a limited resource these days). If for some reason you just have to use a domain hack, register the .com version and forward it to your domain hack, like competitious.com.
7. Keep it Meaningful
We all know generic domain names are hard to come by these days. That, however, does not mean it's hard to come up with a quality name for your company. An easy trick to an effective name is to combine a descriptive word with a meaningful, generic word. Examples include Feed/Burner, You/Tube, Hot/Mail, Tech/Crunch, etc... Make sure the descriptive word gives people a clear idea of what exactly your company does. The meaningful word should make sense and suggest something positive. Naming your startup something like FeedPorcupine or PictureSloth wouldn't fit this rule. Don't do it.