Spare car keys dare
For this you need a spare set of car keys which you leave at home. Drive out naked into the countryside. Get out of your car, still naked and with nothing to cover yourself and lock your keys in your car. (one way is to leave a window open just enough to post the key through the gap.) Now you've done it! You're naked, locked out and some distance from home. You have to walk, get a lift or catch a bus home, still naked. Did I say to keep your house key with you? Once home you can get the spare car key - and clothes if you must - and return to retrieve your car.
A variation is to start out with both keys, hiding one on the way out. Once you have locked your naked self out of your car you must walk back to find the hidden key - if it's still there. Then return to your car. You will be obliged to walk both ways naked. Or you could plan a circular route.
Another variation is a sort of treasure hunt with you as the
treasure. You leave the spare key with a friend with instructions
as to how to find you. Your rescue depends on the treasure hunting
skills of your friend - and the clarity of your instructions. You have to be visible to every passing car so your friend doesn't drive straight past you.