Instructables user instructablesar was sick of his wife taking up both of their family's key hooks. He took matters into his own hands and wedged a small, but powerful, neodymium magnet behind the plastic plate of their light switch.
Now, his key ring hangs automagically from the light switch, and his happy wife gets to keep both key hooks to herself.
If you want to replicate this hack, remove your switch plates and try out the strength of your magnet to see if it can hang on to your car keys through the plate. If it works, you're good to go! Wedge it in underneath the plate like instructablesar did, or just glue or tape it to the back of the plastic plate. Voila!