I think that "world record" thing is pretty dumb. I guess if they're trying to make themselves look important it will be all smiles, but really, who cares?
If you want the Firefox 3 browser without all the fanfare, here's the direct link:
Note: this is the official 3.0 release, not a beta or release candidate.
Important: Don't forget, if you only want to use Firefox as a secondary browser — not your primary web browser — you must un-check the checkbox during install that states "Use Firefox as my default web browser".