My own house, because for some reason the door was double locked, and the key we have only fits one of the locks. So I had to climb over the gate and unlock the door. Makes me realize how easy it is for other people to get in the house.
I once had to break into my own house. I was about 13 years old and my mum took away my key because I got into a fight at school so I couldn't get back into the house until she was there to take away my games. So I walked out of school and used the open kitchen window to get our back door key we kept in the door for some reason and broke in. Then I hid my games and stuff so she couldn't take them away. Bit stupid now I think about it because I got in more trouble for that than i did for the fight.
I forgot my keys home once, but luckily we had a post box/flap on the door, and I was able to use a rake to get to the key rack and catch a keychain that way. My parents weren't too happy about it, so they switched the place of the rack farther away from the door so I wasn't able to do that again ;.;