Description from Knitty.com:

I found this awesome, soft viscose yarn on sale, and knew I wanted to make something for my daughters. Problem: I hate sewing pieces together! So I decided to design something that required NO sewing!

It really is an easy piece to knit. You start at the bottom, working up the front, but instead of binding off at the shoulders you continue over the shoulders and down the back. People may wonder about your long piece of knitting with a hole in the middle, but you'll have the last laugh when you don't have to do any sewing! As an added bonus, the side panels and "seams" are very decorative!

There are many, many variations you can make: longer sleeves, wider sides, etc. You can make the whole piece longer or shorter with ease – it would also look cute as a belly-baring shirt!