Not entirely serious, but what about an underground storage container for your garden? It’d be along the lines of one of those plastic chests, but it’d fit into a hole and come up when you want something. It could even be quite large if you want.
The top could be covered in soil or just a chair or something. It’d be manufactured as a complete sealed box, you just dig any old hole of sufficient size and drop the thing in it. Because the liner would be made as one piece with the lid and mechanism, sealing wouldn’t be a problem.
Useful for those of us with small gardens? And lots of money.. and a thunderbirds fetish…