If I cannot navigate your website drunk, it probably needs better design.
Believe it or not, that’s actually a design philosophy used by actual “I get paid to do this” UX designers. And it’s a really valid one, too. You need to be able to support even the dumbest percentage of your user-base, and what better way to test for that than having drunk users try and poke at your interface?
Of course people rarely ever invite users over for a night of drunk UI testing, it’d hardly be a productive endeavor anyway, but it’s still something to keep in mind. I’ve actually struggled using technology when under the influence multiple times, even though I consider myself rather savvy. Granted, you can’t safe the user from themselves, but you can at least try! If your “downloads” link, for example, is hidden among a hundred other menu items, you’re just making it hard for people to find what they’re likely looking for.
Generally, what “design for drunk” boils down to, is doing lots of hand-holding, guiding the user through your design using visual cues and conforming to the user’s assumptions.