I did it back in November.
It was after a LONG trip home with the bike on the roof.

The nose of the seat hit the entrance of the garage.
This effectively stopped my car.

However, it wrecked the seat, and bent the seatpost back, stretched the forks out with more rake, and cracked the paint at the top tube/headtube lug.

Oh... and it bent the trough on the roof rack.