While not high calorie, I have bought the store package (the plastic barrel) of nori snacks and eaten the entire thing in an afternoon.

One place near a friend's house in San Fransisco runs an all you can eat sushi AND all you can drink sake special for $20. That's just evil. Tasty, tasty evil.

There are a lot of things I used to eat large amounts of that I can't stand now that I've been away from them, especially regular soda.