BSJ Members Speak: Need your help with an offseason football project

Part of the deal here is you, our valued BSJ members, are always part of our coverage and conversation. To that end, I have an idea for a cool offseason project that will be fun for me and, hopefully, entertaining/educational for you.

So here's what I would like to know:

Is there something about the game of football that you've always been curious about/didn't really understand, and would like to know? Has there been a term used by me or commentator that you're not clear on? Is there something specific to the Patriots' system that you want explained better?

Basically, I want to start an online glossary/explainer complete with illustrations/videos to help your understanding and enjoyment of the game. And often, I learn something as well through the process because I need to go ask someone who actually knows what they're talking about.

So what I would like you to do is leave any burning questions/terms in the comment section and I'll constantly refer to it. Remember, these things should be timeless — not, "Why is Jordan Richards still on this team?"

A few examples off the top of my head:

What are the positions on kickoff coverage and what is the typical responsibility for each?
What does it mean to two-gap?
What are the different defensive line techniques that commentators are always talking about?

Stuff like that.

I know you'll have some good stuff.

Cheers!
Greg