Velveeta is a processed cheese that melts well. Growing up my mom would make mac n cheese with Velveeta, butter, and of course pasta. I still have mac and cheese with Velveeta when I get a craving for it.
I also use Velveeta to make Velveeta Cheesy Chicken and sometimes for Better StoveTop Mac and Cheese from a Box.
Want to know more about Velveeta? Check out Velveeta on Wikipedia.