Stopped by one of my fav thrift shops, today. Found these:
http://www.cabelas.com/prod-1/0027561226688a.shtml
in black for 99 cents. They work SO well, I can't even hear my Blue and
Gold Macaw's long range echolocation SONAR, a deafening flock call I'm sure
can be heard at 20 miles in open country.

Sometimes you wanna little "quiet time" where you just can't hear anything.
These are great. I have no data but I'd bet 50db of attenuation would be
conservative. They fit nice without touching your ears inside the cups.

My only complaint is, to get a good seal, the cups are softly padded vinyl
which, of course, makes you sweat. With the intensive internal foam
attenuators, they'd make your ears warm at -50C...(c;

Well, you don't feel it when you're napping in your favorite computer
chair....as life goes clanking and screaming around you....