YouTube has the video MMT for You and Me.
Part 1 rolls right into Part 2 if you keep watching. Part 1 just sets up the question, Part 2 answers it. The whole thing is like 5 minutes long, but it can change the way you view the government and the economy.
If this very short introduction makes you curious, then there are posts all over this blog that point to much more detailed information about MMT.