In the National Football League, playbooks have gone entirely digital. Gone is the old-school binder, replaced by tablet computers in every locker room this season. It's a technological revolution.

There's only one problem: Veteran players can't remember to charge their tablets.

Like any workspace in corporate America, there is a clear divide in the NFL between millennials and the over-30 crowd, who are having a little bit of trouble with the new technology. In particular, they struggle keeping it charged before team meetings, where wall outlets are few and far between.

"My 5-year-old son understands it better than I do," said Oakland Raiders offensive lineman Donald Penn. That said, he added that the tablets have made him a smarter player because he now can watch game film anywhere.

When 32-year-old Houston Texans safety Danieal Manning got his tablet playbook in the off-season, he saw some advantages. Coaches' adjustments would instantly show up on the tablets, for instance, and it was sleeker than an old-style playbook stuffed with hundreds of paper pages.