How many people know how many decibels is dangerous?
74 - that's pretty loud!
74 - that's pretty quiet!
Who knows?

If there were only some space on the billboard for more information.

Dené... droppings?

Excellent use of inattentional blindness... I love the name of a paper describing a similar experiment with a guy in a gorilla suit:
"Gorillas in our midst: sustained inattentional blindness for dynamic events"

Here's a page full of this stuff:
http://viscog.beckman.uiuc.edu/djs_lab/demos.html

Don't worry - if we've learned anything from BoingBoing, it's that some artist out there will create real versions of these within a month.

If you print out a 64x64 grid and tack it to the wall, you have 4096 weeks, or roughly 78.5 years, in an immediately visible, understandable format. Then you cross out each week as it goes by.

You can shade in some relevant boxes (graduations, job changes, marriage, etc) to see where they occurred in your life.

I find this a lot more salient than some high number (like 8500) of days remaining.