These guys decided to invite gramps over to play video games, specifically, Black Ops 2. Now, Grandpa is 84 years old, so I'm assuming the guys just expected him to be confused, play for a minute then give up. Not the case! Grandpa really seemed to embrace it and have a blast!
Give the video a watch. You'll want to invite the first old person you run in to over to play video games with you!