Texture Stretching

How do I keep textures from getting that stretched appearance when I put them on an object that has been stretched a lot.

There are several ways to do that, probably the easiest:
ScaleTexture.

Ya, but the cubes I'm using are only scaled along the Y-axis, and a lot (to give them the appearance that they go down forever), so scaling the textures would make it look good on one side but not the other.

Apply the texture to your stretched object in your modeling application such that it looks okay. No need to do it in code unless you are altering the texture/object scale dynamically.