Here are my Guaranteed Waterworks moments:
Casablanca: the scene where everyone stands up and sings the Marseillaise (which is nearly everyone's favorite tear-inducing scene, apparently).
The Return of the King: the beacon-lighting scene, and Sam lugging Frodo up Mount Doom, and, for that matter, quite a few parts after that. (Told you I was a big sap.)
The Shawshank Redemption: when Tim Robbins' character broadcasts the duet from The Marriage of Figaro to the entire prison and all the convicts stop in their tracks and look up, trying to figure out where the music's coming from. Though this has as much to do with the choice of music as with the scene itself.
Grand Illusion: de Boeldieu's deathbed scene, especially the part where von Rauffenstein snips the one flower off his scraggly potted geranium. And Maréchal and Rosenthal's reconciliation after their quarrel on the way to Switzerland.
Babette's Feast: the very end, when the dinner party breaks up, and the sisters tell Babette that in heaven, she'll get to be the great artist she was meant to be on earth. And we see that all the characters have had to set aside their ambitions and become something other than what they wanted to be, and yet there they are, looking up at the stars, looking at each other. That gets me every single time.
The reliable laughter moments are more frequent and thus harder to list off the top of my head. However: too many scenes in O Brother, Where Art Thou? to enumerate, and pretty much all of Jack Black's dialogue in High Fidelity. And I am geeky enough to still chortle at Monty Python after all these years. (Favorite bit from The Life of Brian: "You don't have to follow me! You're all individuals!" Crowd, in unison: "Yes! We're all individuals!" One lone voice in the background: "I'm not.")
If we expand it to include books as well as movies: The last few paragraphs of Joyce's "The Dead" always, always make me choke up ("Yes, the newspapers were right: snow was general all over Ireland..."). And — oddly, considering what a heathen I am — so does Milton's Nativity Ode, especially stanzas 12 through 16 or thereabouts, and the very ending of Paradise Lost. If we expand it to include music, I invariably start to weep partway through the trio in Act 3 of Der Rosenkavalier (to pick one among many instances), not that regular readers of this blog don't know that already.
Over to you, Reader. What are yours?