I just learned about Bob Ross a few days ago and immediately bought a DVD, a book and his starterset for the knife and liquid white.
And all I can say is, that the outcome is amazing.
I really love how simple it is. I always considered colours as my personal enemies... But with his idea of a liquid white background layer, you can use almost any colour you want and it will blend in perfectly.
And it is just fun watching his videos.
So if you are interested in quick and easy and most wonderful paintings, don't miss his ideas. :)