The episode opens with Barney at laser tag where eventually he gets banned for life when he uses a kid as a human body shield. Barney tries to get Ted to help him toilet paper the laser tag, but Ted tells him he's too old for tp'ing and adds it to his Murtaugh list. The Murtaugh list is based on Lethal Weapon's Roger Murtaugh (Danny Glover) whose catch phrase is "I'm getting too old for this sh..." err stuff. Barney tries to prove that they're never too old for things and they make a gentlemen's bet. If Barney can complete everything on the list in 24 hours, Ted has to go with him to tp the laser tag, if he loses he has to listen to Ted ramble about architecture for hours.
Barney goes with Robin as his judge to complete the tasks and they eventually up the odds and make Ted complete Barney's list of old man tasks, including eating dinner at 4 and in bed by 8. In the end, Barney is unwilling to do a beer bong in the morning and gives up. However, Ted spent his night watching Lethal Weapon when he had to go to bed so early and ended up tearing up his list. Despite Murtaugh always saying he was too old for this sh... stuff, he always did it. Ted decides to go with Barney to TP the laser tag.
Meanwhile, Marshall helps Lily out by coaching her students in basketball. She's using it as a tes tto see how he'll be as a far. Marshall ends up being ridiculously tough on the kids and Lily makes him loosen up, the kids are just meant to have fun. When they have the game, the kids get their butts whoops and Marshall begs her to let him coach his way at halftime. She does. During the second half they get whooped even more when somehow Teen Wolf joins the opposing team. Hilarious.