Extruding Meshes and Title Screen during gameplay

Hi guys, I have two issues that I need help on.

  1. Is it possible to extrude meshes? I realize the wall meshes I used from the start content folder is different from the box brushes that can be extruded easily.

  2. I am trying to make a fade in/out title screen during gameplay. The title screen would fade in as I start heading down in an elevator scene.

Thanks a lot guys!