Before you start coming up with cool names for your site, think about what you want to convey about it. What types of services are you going to offer? What features and functions will the site have? What type of site is it -- social networking, educational, or something completely different?
Sure you can come up with a name that has nothing to do with its purpose -- obviously Amazon.com and a host of Web 2.0 properties have done it. You could coin your own phrase by inventing a pseudo word for a site name, which might start a verb trend (ever heard of "googling"?). GoDaddy.com CEO Bob Parsons talks about strange domain names on his April 6, 2005 podcast, if you're interested.
Keep in mind that you want your domain name to be brandable and memorable. I'd be glad to give you some ideas, but it would be better to know -- what is the site's purpose or, better yet, (aside from the "funny" tag in your question) what do you want the user community to remember?
If you really want to create some buzz, stage a contest to name the site. You might even be inspired by this guy who offered to change his name for the highest bidder.
Meanwhile, while you're trying to figure it all out, here are a few helpful links to get you started on domain name brainstorming or "namestorming." These sites have wizards that combine words and can suggest domain names.