Clear Card
I received my Clear card in the mail a week or so ago. This is the expedited security check service at US airports, based on submitting to a background check and being biometrically profiled: turns out my eyes are too shifty to be retina-scanned (or the machine was on the fritz), but fingerprints worked alright.
The other day, I showed up at Dulles with my Clear smartcard. The line is on the first floor, nowhere near the usual security line for travelers, immediately next to the line for employees. The line for Clear was zero people — literally no people. There were seven or eight employees lined up, but I walked up with no delay. Stuck in my card, press my index finger to a plate, approved. Then went through the security check in the usual fashion, just with no other people around. Sweet.
If you decide to sign up — and you should — there is a fee: $128 for the first year. Would make a great gift for a busy traveler. I think I could save 30 minutes at the typical airport during crush times, especially in the summer when the tourists jam everything up.

If you opt to sign up, please use this referral code: DSCAM1159566. I get a free month for a referral. Thanks!