That sounds really fun but it's summer here so I came up with a something I could try now instead of waiting another six months for snow. I call it
Trapped in the Dungeon.
I live close to the beach so I thought the next time I go down there I could bring along a spare bikini and leave any other clothing including towels behind. My aim is to dig a hole in the sand and bury my spare bikini then build a sandcastle on top of the newly covered hole so I know the spot where my swimwear is buried. In essence making the hole the castle's dungeon, the sandcastle isn't really necessary (a stick could be used or some shells) but I like making them dammit.
Afterwards I'd go for a swim and conveniently
lose my swimwear in the ocean. The longer I take the more chance I have of something happening to the sandcastle and losing place of where my bikini is buried. Worse case scenario I'd have to run home naked!
Well it's just a variation I'm going to try, I tried to keep it in the spirit of your dare, thank you for coming up with it!