After class ends, their history teacher asks to see them before they leave. Before he can even begin informing them of the obvious fact that they're not doing too good at the class, they preemptively attempt to express their gratitude for all that they've learned from his class. When the very incredulous teacher asks them what it is exactly that they've learned, they credit him for letting them know that the world is full of history, with great leaders such as Genghis Khan, Joan of Arc and Socratic Method.
Bill and Ted's roundabout conversation at the beginning.
Bill: Ted, while I agree that, in time, our band will be most triumphant, the truth is Wyld Stallyns will never be a super band until we have Eddie van Halen on guitar.
Ted: Yes Bill, but... I do not believe we will get Eddie van Halen until we have a triumphant video.
Bill: Ted, it's pointless to have a triumphant video before we even have decent instruments.
Ted: Well, how can we have decent instruments when we don't really even know how to play?
Bill: That is why we need Eddie van Halen.
Ted: And that is why we need a triumphant video!
(beat)
Both: Excellent! (Air guitar)
The entire "Gathering the Troops" (historical figures) montage.
All the historical figures cleaning house, especially Sigmund Freud and the vacuum cleaner.
Complete with the fake aliases (except for Honest Abe, who's introduced with his real name). "Bob Genghis Khan" may be the funniest phrase ever said on film.
Not to mention the historical figures running amok at the mall, especially Joan of Arc's jazzercise session and Genghis Khan's sporting-goods rampage.
And Billy the Kid starts shooting just for the fun of it, followed by Socrates joyfully trying to imitate him with a little dart gun.
Billy: Yee ha! (fires a shot into the air and runs off)
Socrates: Yee ha! (fires a toy shot into the air and gives chase)
Socrates carries a lethal squirt gun.
Billy The Kid and Socrates hitting on women and Freud tries to butt in. He is then called a geek.
Freud is holding a corn dog while they're conversing with the girls. He lowers it when the girls start laughing at them. Freud Was Rightindeed.
The historical figures' oral presentation. Most notably, Ted calls out on Napoleon's strategy (regarding the use of a "Water-slide" aka Waterloo)
Bill and Ted bringing Beethoven with them. They come up to him while he's playing, and when he won't listen to them, they just up and carry him off the piano. He was so distracted, he was playing, well... air piano.note While it is known that Beethoven had become almost completely deaf towards his final years - he died in 1827 - The Other Wiki points out that he could still hear music normally by 1814, and the film states outright that B&T brought him from 1812. So this can be easily chalked up to distraction, or pure Rule of Funny.
Also, Socrates randomly bowing to the nobles before they all leave.
Sigmund Freud vs. the police examiner:
Interrogator: Look, I want to know why you claim to be Sigmund Freud.
Freud: Why do you insist I'm not Sigmund Freud?
Interrogator: Why do you keep asking me these questions?
Freud(leans forward): Tell me about your mother.
Camera shifts elsewhere.
Freud: Would you like a couch to lie on?
Interrogator: No, I do not want a couch to lie on!
The movie's final line from Rufus: "They do get better."
When Future Bill and Ted first land outside the Circle K, you can hear one of them mutter, "Oh, I hate this part" as the phone booth makes a rough landing.
Bill and Ted distracting Ted's dad by rigging a trash can to drop from the ceiling; written on it is "Wyld Stallyns Rules".
Bill & Ted's Bogus Journey
De Nomolos invokes the infamous air guitar Bill and Ted displayed in the first film as part of his manifesto, in his... Unique way;
De Nomolos: ...no longer will we hear this!—
*strikes an air-guitar pose and some bass-heavy grinding immediately sounds off*
Bill and Ted explaining why their girlfriends/fellow band members are able to play better than they themselves.
Death to the smoker at the hardware store: "See you real soon."
Followed by the guy doing a double-take and quickly stubbing out the cigarette.
From the Spinning Paper Montage: 'Death Wins Indy 500; "I didn't know I could run that fast."'
B&T Melvining Death, of course. Made even funnier in the comic adaptation with this follow-up.
Ted: Bill?
Bill: Yeah?
Ted: Death wears funny shorts.
The Good Robot Usses decapitating the Evil Robot Usses is funny in itself, but the fact that the Evil Robot Usses are so nonchalant about it makes it hilarious.
Evil Robot Bill & Ted: Well played, human usses!
De Nomolos's Mooks seizing control of a room using typical action-movie-thug poses and body language, dressed in standard-issue paramilitary black ... and giant floppy black boots made of polyethylene foam, which are apparently all the rage in their time.
The couples therapist provides a lot of straight man comedy as the film takes a turn for the fantastical.
At first she assumes she's dealing with normal women married to delusional airheads, until Liz and Jo casually confirm they were princesses born in 1408 and 1410.
Bill and Ted's creative prowess is about as confusing as their regular train of thought, as their performance at Missy and Deacon's wedding can attest.
On the subject of Missy, her Running Gag of husband-hopping continues here, turning the Logan family tree into a messy tangle.
Bill: Best of seven?Death: DAMN RIGHT!