The entire "To Russell, My Brother, Whom I Slept With" routine from the album of the same name. It's a 22-minute routine on nighttime hijinks involving an undersized bed (on which he and Russell keep fighting over sides), a grouchy father, and tall tales about who broke the bed. Their father continues to threaten to come in with thebelt to spank them both, which will "rip the meat off of their bodies" should it hit them. Realizing that neither boy will go to sleep, the father forces them both to stand up on the floor until morning. The skit ends with, "I don't want you touching me on my side of the floor, either."
Also, what has popularly become known as "the Noah routine". Actually three short skits, riffing off what would actually happen were Joe Random Citizen one day asked by the Lord to build an ark (for one thing, his neighbor would be really cranky when it blocked his driveway...) Please, if you're currently blank-faced, go listen to this thingright now.
"How long can you tread water? Heh heh heh.."
Became the world's longest Brick Joke when Bill hosted a Kids Say The Darndest Things special. He asked a little boy what his name was. When the boy said "Noah." Bill looked at the audience, smiled and said "Riiiight!"
The dentist skit for its exaggerated portrayal of going to a dentist. He makes some priceless facial expressions as well.
The infamous "It's True, It's True!" routine, wherein Bill relates the time he was in Japan and decided to see for himself whether the rumors about those "wonderful baths" were true... but his wife walked in on him.
The routine on "Go-Karts," which features a multitude of great sound effects, as well as a Call Back to an earlier routine about Cryin' Charlie, and a Brick Joke involving the cops.
The fernet branca routine, wherein bitter liquor saves the day after he accidentally orders barbecued sparrow at an Italian restaurant while trying to impress his wife.
Every sketch involving Fat Albert.
Breathing "macho style" with his wife in Lamaze class. It builds to the point where he's getting so into it that he imagines them going to parties and being asked to do their routine for impressed audiences...
Ladies and gentlemen, the breathing Cosbys!
"Natural childbirth means that no drugs will be administered into the female's body during the delivery. The father can have all he wants."
His mother's hypocritical parenting: "Day and night, night and day, work my fingers to the bone, for WHAT?!" "I don't—" "SHUT. UP! Now when I ask you a question, you keep your trap shut!"
"You know what my father's favorite game was? 'Come over here and pull my finger!!'" And, of course, from earlier, we have what Bill thought his name was thanks to his dad's swearing.