TechCrunch reported yesterday that Encyclopedia Britannica is granting one-year free access to "web publishers." If you're a blogger, webmaster or someone "who publish[es] with some regularity on the Internet" you qualify.
If you're interested head over to Britannica Webshare and check out the details. You have to click on "register" and fill out a short form that includes the URL of your site. I got a response in less that 24 offers that included an offer code that allowed me to "order EB for one year.
I'm not sure how often I'll reference Encyclopedia Britannica, but it's a $70 value. That's access to 44 million words of quality information for free!