Boat Game 1
Lie on the floor and feel how it pushes into your back and shoulders. Concentrate until you can feel the planks, the joins between them and the nails holding them in place.
The game is over when you have lain on every part of the floor and are able to reproduce an accurate map of it in your mind: every plank, every join, every nail, every hollow, every bump, every scratch, every smooth patch, every area of roughness.
Boat Game 2
Run your finger over all the edges you can find, for example, the corners between walls, the edges of the furniture, or around the windows inside and out between the frame and the wall and the frame and the glass.
The game is over when you have begun and ended at the same point, and in between have touched every edge along its entire length, without ever having had to lift your finger and without having had to go over the same edge twice.