I used to have a big problem losing my keys all over. Even in my room. I've gotten over it, but something like a magnetic light switch cover would've helped a lot in those formative years.
It's exactly what it sounds like. All you do is stick your keys on the switch and forget about them... until you need them again. And the magnet's strong enough to hold a hefty carabiner if you've got keys for literally everything you do. This thing is a godsend. $US25. [The Fancy via OhGizmo]