Looks to me he built a PacMame cab. These use a TV mounted inside a low height cabinet for children, munchkins and people who like to wear out their knee caps.
It looks like he has one of those TV game systems hooked up to it. Nice cheap and perfectly legalish. So the RCA goes into the TV's composite connection. I did not see anything about VGA, but if you have a Magic VGA you can do the same thing with a LCD display.