A way to make TNT more available.

It's a little known fact that mining with TNT is actually a very effective way of not only clearing out a large area in cave systems or anywhere underground, but it is also an effective mining strategy when the player knows how to control the explosion. Currently, in order to obtain a TNT block, the player would have to go on a creeper killing spree or setup a creeper farm. Not saying that TNT should be entirely easy to obtain, but it would be nice if this block didn't feel so end game. Please give us another way of obtaining TNT.