Over the last few seasons, the run-pass option (RPO) has become increasingly popular in the NFL. The way it allows an offense to react to how the defense lines up and then reacts off the snap of the ball makes it easy to avoid negative plays that flow right into what the defense is doing, and without resorting to an audible that would alert the defense that the play has been changed. 

Of course, the RPO hasn't always been this popular. There was a time where it didn't even really exist. Now, the invention of the RPO is not generally credited for Green Bay Packers legend Brett Favre, but if you watch the video below, you'll see that he was thinking along those lines during his career. 

Check him out talking to Jon Gruden on Gruden's QB camp about how he essentially invented the run-pass option because he was bored handing the ball off in practice. 

"I'd get up there and it's a run play and I got nothing to think about," he said. "Just handing off. Not only was I kind of bored with the hand-offs and all, I was trying to be creative and spice it up. But I thought to myself, 'Damn, that guy's wide open.' Now, if I had changed it to a hitch or something but maybe [the cornerback] comes up ... Now, the play's not as good. So, why not just do nothing? So in practice, I was like, 'Hey, if the run's away from you; no matter what, just run a little one-step slant.' We call it a look."

That, essentially is an RPO. They're more complex not and they're designed into the offense, but that's it, right there. Pretty cool stuff.