Left my passport at the RCC in SFO on my way to YYZ - I was able to get on the plane without it, and through Immigration in YYZ without it *phew*. Reported it lost to SFO Airport police and the Passport office.

Signed the declaration, and got my new passport in a week (I paid the extra to do this).

The day I got my new passport, an envelope arrived from SFO with my old passport.

I then returned it to the Passport office. Subsequently, I got a NEXUS card and have only done the secondary shuffle once (driving into the USA) which was no real hassle.

-Brian