Or the world's most persistent cat! We have a microchip controlled cat flap and, after Harry got himself shut in next door, we didn't want him to go out quite as early. DH has a bad back and I've been struggling after an operation so, rather than adjust the time, we put a box in front of it. That was moved and I was woken up by him letting himself out.
The next night we put a box half filled with glass Budweiser bottles - again, he moved it and went off out. Last night it was a full box of Bud - you've guessed it, he got that out of the way as well! DH has just managed to get down to change the times as I don't think we've got anything heavy enough to stop him!
I shouldn't be surprised though - we've got floor to ceiling sliding doors in the bedroom and Harry can open those from closed to find the only bit of carpet in the house so he can sharpen up!