Jim wants to know if he can use his old Atari gaming console with his new TV. Leo says there are ways to do it, but he will need a "composite" adapter to do it. Most modern TVs don't have composite inputs anymore. Those are the red, white, and yellow connectors. You may also need an antenna adapter. Jim will need to get a composite to a digital connector which may actually cost more than that old Atari game is worth. But he can get one from Monoprice for under $20. Don't expect great video though.
From the chatroom - here's an article showing how to do it from AtariAge.