This 14 minute animated video is a nice introduction to the Three Sectoral Financial Balances, which are an important part of macroeconomics, or the study of the economy as a whole. The dialogue sounds a little odd, but stick with it.
The video helps to dispel some myths about the desirability or otherwise of government budget deficits and surpluses, and how the associated money flows interact with the rest of the economy: the private sector (firms and households) and the foreign sector (the rest of the world).
In particular, the discussion outlines how the US government ran budget surpluses in the late 1990s, but also how this was more than offset by the private sector deficit, and the resultant accumulation of private debt, which ultimately proved unsustainable.
The post-Keynesian economist Wynne Godley, originator of the Three Balances approach, warned about this in 1999 here, and forecast a recession, accompanied by rising unemployment and government deficits, as these trends necessarily began to unwind over the medium term.