When I was in high school, I was on vacation in DC with my brother and my parents. We were like a block away from the White House and my dad found like $800 in cash on the ground. He decided, like only my dad would, to turn it in to the cops in front of the WH. They made him fill out some paperwork to place an ad in the paper. Then we started to walk back to our hotel. We got several blocks when a Suburban pulled up on the wrong side of the street and the cop my dad gave the money to got out and explained he was secret service. They couldn't believe what we did and offered to give us the real tour of the White House. They gave us a tour of everywhere you don't get to see: Oval Office, The Press Room, bricks left over from when the WH burned down, the Lincoln Statue outside the Oval Office, etc. They told us great stories. Two quick ones: To enter the Press Room, you have to go outside the White House and down some steps. It was originally going to be a pool but Nixon's approval ratings were low so he made it into a Press Room. (it's REALLY TINY!) The most guarded object in the WH is the Nobel Peace Prize, there is one SS guy there to protect it at all times.
Funny thing is my sister was really bitter because she wasn't there, now she works in the White House, Office of Management and Budget.

btw: no one claimed the money and we got to keep it!