In the new 1.4.2 update, many things were added! While I was bored, I decided to explore some things! And I discovered the greatest thing of all time! Wanna do it too? Here's an easy guide!!!
1) Create a new world, and make it superflat.
2) Click 'Customize' and then click 'presents'
3) Scroll down to 'Redstone Ready' and click that
4) In the top box that says all those crazy numbers, replace '24' with '46', and get rid of village
5) Create your world
6) Spawn some Flint And Steel and have fun lagging your computer to the point where it explodes.
Well, that's how I did it! I'll tell you guys what happened after I blow up my computer! You can also do this other ways, like clear out the type box and just type 46, but then the TNT falls into the void. So, have fun creating your own wacky TNT/computer blowing up worlds!