Quck and easy, and good cold as well as warmed! I use it in my bentos sometimes. Very simplified version that most recipes you'll see, but it works good.
1 tablespoon sugar
1/2 teaspoon soy sauce
Mix everything in a bowl, starting with beating the eggs first and getting them a little smooth before adding the sugar and soy sauce. Get everything nice and smooth and heat up a NON-STICK skillet. Melt a little butter/margerine in the pan to coat it, then pour in the egg mix so it covers the bottom of the pan. Let it cook on medium-high heat until the edges are kinda dry, then carefully work a large spatula under one edge and start rolling it up. If you kinda flip the edge up and fold it over about an inch, you can just repeat the flipping until it's at the end. This takes some practice, so don't worry if you don't get it the first time. It's still a tasty mistake! Anyhoo, once it's folded up, cook the egg until both sides are done and VERY lightly browned (i'll take pictures next time i make it so you can see). Then, just slice it up (it's tender enough to do so with the spatula) and do whatever you planned with it. You can top it on sushi rice for tamago nigiri, or just eat it alone. I like to stack it in my bento for a change from hard-boiled eggs, but I occasionally make it to go with supper too.