Go on Superflat mode on a desert and take away everything but the sand. When you spawn you wont fall right away. You have to keep digging down until you reach the bottom. Then prepare for the biggest lag EVER! It beats every lag machine you and all the other people in minecraft build. This will resault as only void. Maybe you can create a little survival island before you dig down (Only if you don't have SinglePlayer Commands or how ever they make survival islands :P )