I get the latest snapshot, get my redst0nez out of creative, and build this. Actually, my friend is paying me about $60 to make this giant TNT cannon for him. Here's a picture of what I've done. If anyone wants me to do a video of me demonstrating it I will! I probably should anyways to show him what I have done. Its completely automatic. You put TNT in a chest over at the left. then it gets transported all the way to the dispenser. Then you hit the wooden button and TNT comes out. God I hope Hoppers will be enabled on ECC.
Hmm, how much would it cost me to have you rig up redstone lamps that turn on when the sun goes down?