In this technology age, there are still some common sense inventions that nobody's though of yet.
Remote Control for your lights: They have something like that for lamps or lights that plug into the wall. But why don't they have a remote control for the ceiling lights that operate with a switch? Haven't you ever been so comfortable in the bed that you were just ready to fall asleep but you couldn't because you had to get up to turn off the lights?
A Shower that doesn't act up when someone flushes the toilet
Self-heating toilet seat so you don't freeze your "assets" off on those cold winter mornings
A dryer that doesn't eat up all of your socks