I once went to an all-you-can-eat buffet in Bulgaria with a mechanism I'd never seen before.

The salads and starches and suchlike were all self-service, and waiters toured the room with big skewers of freshly roasted meat they'd carve right in front of you. But of course they'd only serve you a certain amount, and they weren't very fast to make a return visit. Thus limiting diners' consumption of the more expensive items, unless the diner was very patient.

Of course, the prices were very fair and we all left well fed.