A list of things that a person of a certain age is to old for. Named after Murtough from the Lethal Weapon movies who keeps saying, "I'm getting to old for this stuff." Also this list is made famous by the T.V. show 'How I Met Your Mother'.
Nic: "So I just got done throwing water balloons from the top of the building."
Tyler: "Dude, we're getting to old for that."
Nic: "What do you mean?"
Tyler: "I think it needs to go on the Murtough List."