Buy a toilet with a tank that holds more than 6 liters
Use an incandescent light bulb
Buy an oven that can get hot enough to cook a pizza properly (except when in self-cleaning mode when there is a locking mechanism preventing you from using the high temperature to actually cook)
Detect a radar signal someone is beaming into your car unsolicited
Unscramble a TV signal someone is beaming into your home unsolicited
More examples later — add your own in the comments. I’m pretty sure these are all unconstitutional prohibitions.