Raoul confesses something he learned while eavesdropping on Christine for the second time. To paraphrase, a very annoyed Christine asks, "You were listening at my door again?", and (to further paraphrase) Raoul answers, "Of course not — I was hiding in your closet."
Richard's and Moncharmin's attempts to catch the Phantom the night he extorts his second payment, which includes walking backwards all night and the crazy incident with the safety pin that makes the poor secretary Remy think his bosses have lost their minds.
Erik's sarcastic letters to the managers near the beginning, particularly the names he calls the other performers.
Piangi attempting to scale the mechanical elephant in the "Hannibal" scene.
Carlotta's diva rant shortly thereafter ("'These things do happen'? You've been here five minutes, what do you know?!").
The very long low note done by the old cuckold in "Il Muto".
The low note has, by now, actually earned the cuckold his own round of applause in most theatres.
"The role of the pageboy is silent, which makes my casting, in a word... ideal."
Michael Crawford's delivery of that line on the London cast album is delightful. And just try not to smile a few minutes later when he spoils Carlotta's performance and accentuates it with a wonderful Evil Laugh.
Ramin Karimloo can also give Crawford a run for his money with his laugh.
All the Phantom's funniest moments are actually when he's offstage; he's a savagely witty Deadpan Snarker who just loves insulting people via his little notes.
This little bit in the song "Notes/Prima Donna". "And what is it that I'm meant to have wrote?" Beat "Written."
It doesn't come across very well on the original cast recording (or the movie, unfortunately), but the managers can be absolutely sidesplitting in the right hands. Firmin Deadpan Snarking his lines in "Prima Donna" or Andre fumbling his way through the "ballet from Act Three" speech are among the many delights Those Two Guys bring to the show.
I happen to find nearly everything Carlotta says or does to be so over-the-top that she is one of my favorite Characters That Don't Matter Much in The End. Especially her aforementioned rant after Hannibal, especially how it was done in the film: "For the past three years these things do happen? And do you stop them from happening? No! And you two! you are as bad as him! 'These things do happen?' Ma, hmph! Until you stop these things from happening THIS THING-" *points at self dramatically* "-DOES NOT HAPPEN! UBALDO! ANDIAMO! BRING MY DOGGY AND MY BOXY. Now you see, bye bye, I'm leaving!"
Kind of darkly funny, but this exchange during the "Don Juan Triumphant" rehearsal never fails to amuse me:
Carlotta:(re: Piangi's incorrect singing of the score) His way is better; at least he makes it sound like music!
Mme. Giry: Signora, would you speak that way in the presence of the composer?
Carlotta: The composer is not here! And if he were—
Mme. Giry: Are you certain of that, Signora?
*cue massive Oh Crap take into the flies from everyone onstage*
And when Carlotta sits back down and Pingi tries to sing his lines again, everyone huddles in close, fast as lightening, to hear him get it right. The pressure does not help.
The 25th Anniversary's version of this scene has a couple of gems. First is Piangi's line: "If you can call this sh—gibberish art!" And, second of all, La Carlotta parades around the scene wearing a hat that looks like an enormous Jammie Dodger on her head.
The 25th's managers. Everything they do is incredibly funny in a suitably subtle way, with the two actors engaging in some very rapid line switches between each other. Not to mention 'Prima Donna', an entire song devoted to satisfying her ego.
Firmin and Andre:
Who'd believe a diva happy to relieve
A chorus girl whose gone and slept with the patron?
Raoul and the soubrette, entwined in love's duet!
Although he may demur, he must have been with her!
You'd never get away with all this in a play,
but if it's loudly sung and in a foreign tongue
It's just the sort of story audiences adore, in fact a perfect opera!
In addition, there is the Phantom himself. At first he appears to be perfectly cultured and civilised, but after Raoul and Christine get together he starts to break down into a goofy Card-Carrying Villain. First there was the Masquerade, where he interrupts wearing, um, this◊. Then the mask comes off (which...wasn't a terribly good idea after what happened last time), and, well, he tries to make Christine marry him. Really, he'd have grown an Evil Moustache by that point if if wasn't for, y'know◊...
Depending on the actor, the Phantom can be hilarious during the early bits of the Final Lair scene. Particularly if he's sitting on his throne and giggling half the time...
It's certainly a Tear Jerker and a Crowning Moment of Heartwarming and so on...but honestly, Erik's bug-eyed shock when Christine kisses him in the Final Lair scene is kind of funny as well. (I know, I know, I have no soul...)
When Erik finishes singing 'Music of the Night', he proudly unveils a life size mannequin...that happens to look exactly like Christine, and is wearing a wedding dress. That would be bad enough (and it's pretty clear that Christine doesn't know what the hell to think of this) but then the frigging thing comes to life, jerks out towards her and causes her to faint. Whether she ends up in his arms or on the floor, Erik's reaction generally seems to be 'Whoops, didn't intend for that to happen.'
Actually, just the fact that he has a life size doll that looks like Christine, all done up in a wedding dress, in the first place - when it's not being creepy. What's the deal with that thing anyway? It's never explained.
The escalating chaos of 'Notes', where everyone is bursting in and accusing everyone else of things they didn't do. One can imagine the Phantom spying on the resultant mess and having a good laugh at their expense.
Madame Giry: "Please, monsieur - another note."
Everyone Else:: *Collective groan*
It's cruel, yes, but it's also quite funny to see the Phantom clearly getting all hot and bothered when Christine starts her bit in 'Point of No Return' - trembling hands, clasping knees, the works - plus she gives him a taste of his own medicine when she starts running her hands all over him!
From the Arthur Kopit/Maury Yeston musical, we have the Phantom's initial reaction on hearing Carlotta (in this version a Dreadful Musician who only gets leads because her husband is the manager):