We built a boat this summer. It's called a Mouse. It is 8 feet long and made from 1 and 1/2 sheets of 1/4 inch luan plywood. We got the plans from the book Ultrasimple Boatbuilding by Gavin Atkin. It was easy and the boat is awsome! We will be building more. (one isn't enough for 4 people...) Here's how it went for us.
This is the book we used.