Removable Menu Items in Restaurant
This is one of the ideas where everyone I tell it to always agrees it would be great, but it still hasn't been implemented just YET. So, if you are able to get it done right, it's your chance to become famous!
The invention yet to be made is a restaurant menu that you can gradually whittle down to what you would actually like to eat. More often than not, people go through a menu and can't decide what they want, but at least they know what they DON'T want. To help the process, it would be great to be able to eliminate those dishes that you have ruled out, so you can more easily decide between what's left.
The obvious solution would be some kind of touchscreen where you can simply click away menu items - but that's actually way to expensive for most restaurants (imagine every menu being a computer!), plus, it might actually frustrate customers - well, at least it would frustrate my Grandma.
So how about an analogue solution for a change? Simple tabs that you can push in, leaving those menu items marked that you might still want. There are still various issues to be solved, however: The waiter, for instance, needs to be able to reset the menu quickly for the next customer, plus, the whole setup needs to be appealing and not look like the gritty sheet of some dock worker who's trying to keep track of his warehouse.
Reward: Free restaurant visits would be nice!