“A million bulbs would contain 1000000/5660 ounces, which is about 176.7 ounces, or 11 pounds of mercury. It’s a bit more than you suggested, but not life-on-Earth threatening.”
So renaming this thread “How many congressionally-approved light bulbs does it take to screw your kids?” may not make much sense.
It's a plausible question, but the answer will be a large number. Of course, one might argue that a billion or several billion flourescents is a much larger number than we were talking about. In that case we're talking about 1/2 a ton per billion flourescents, or maybe a tractorload volume of mercury.
Maybe the right conclusion is that recycling is a good idea since there are so many, but panicking over the 5 mg in a single busted bulb in the house is idiotic.