As the title states: What are some strange things you've done in games, or while playing games?

Skyrim is a great game for this.
For example, in Skyrim I like to pick up interesting things and arrange them tastefully in my house in Whiterun. At one point I had 3 Statues of Dibella sitting nicely on a shelf all facing the same direction - unfortunately the game erased them at some point.
I also made a point of collecting the Glenmoril Witches' heads and then hiding them in places around my house. I currently have one sitting on a plate next to my bed and another cooking in the fire under the cooking pot.
Another thing I did in Skyrim was TAI an entire town whilst they were going about their daily business. The town suddenly felt a bit... creepy.

In Deus Ex: Human Revolution sometimes I would confine myself to using only vending machines as both cover and a weapon. I would drag the vending machine with me wherever I went, whenever possible. Also secretly punching out people who I disliked on the streets.

In Shadow of the Colossus I would always jump off my horse and shoot lizards, even the ones who don't give you anything for doing so. I also wasted a lot of time trying to shoot the doves around the altar at the starting area.