Explain Football to Foriegn Students

[play, coach or ref]

Anybody got ready-made briefing I can use to explain the American high school football game to a group of foriegn/international college students?

I've got 20 to 30 minutes to explain the game on Thursday, Nov. 11; and then these students will attend a local high school game on Friday night, Nov. 12.

(Yes, I know that Thursday is Veteran's Day -- I'll slip in an explaination of that as well!)

All help is appreciated!