How and with what software do major television companies display on-screen graphics during their programs?

For example:

On ESPN, how do they produce the news ticker on the bottom (both graphically and from a source code point of view), create and display the scores of sports, and update and show selected stats on the fly?

I've looked everywhere I can think of to find the answer, but I am at a loss. That's where you guys (and girls) come in. I hope you can help shed some light on this subject for me. Thanks in advance.