Oh, mothballs - mostly these are ships or planes that are being scrapped, the problem is that there is a waiting list - these make for great hideouts and locations for special events, like fight clubs and gambling dens.
I've used an art gallery a few times with great results.
It is especially fun if the art pieces are fragile sculptures and the PC's are motivated to avoid damaging them, such as if they are responsible for paying for broken pieces.