There were a lot of impressive illusions in the musical The Magic Show many years back, since it starred the magician Doug Hennng. He also appeared in the less successful musical Merlin, which also featured illusions.
The Flying Sequences in Peter Pan, Mary Poppins. the aerial work in Billy Elliot, the Transformation in Beauty and The Beast and defying Gravity in Wicked.
I agree with Mary Poppins and Wickeds flying sequences. My favorite though is the boat scene in Phantom. I don't know what it is about it but it just gives me chills. Oh and I liked the part in Shrek where they were traveling across the lava on the bridge and they had high power smoke burst out of the floor with lights on it to look like flames.
When Martin Short (in the Goodbye Girl) stopped rowing the row boat in Central Park and it just kept on going. He made some crack about it and it was absolutely hysterical. Wish I could remember exactly what he said.
Starlight Express in London was beyond fantastic (experience-wise) - you seriously never knew where the action in the theatre was going to happen next. And the way the tracks and the big bridge reconfigured throughout the show was really amazing.
9-5, I think the song is 'potion notion', when a big sheet covers Alison Janney and the whole stage, the sheet gets pulled back to reveal Stephanie J Block and Megan Hilty with Alison.
Woman in White, 'A gift for Living Well', Fosco puts a red handkerchief in his clenched fist, to then pull out a blue one.
The train coming out of the tunnel in the end of Woman in White.
The flying car in Chitty Chitty Bang Bang.
The blazing bed in Woman on a Verge of a Nervous Breakdown.
Spamalot where the knights arms and legs are dissected in the door.
Phantom, Masquerade when the Phantom walks down the stairs then just disappears at the bottom. Love the pyrotechnics in the Las Vegas production.
The hanging in the end of Young Frankenstein.
As others have mentioned of Mary Poppins.
I might not be a lover of all the shows above, but when a show has a good stage trickery in it, I respect that.
^Javert's Suicide (in the 25th anniversary revival tour) was f*cking amazing. I did hear that in the original production(s), javert's corpse was carried offstage by the turntable with blue-ness (water) engulfing him.
I saw Mary Poppins in London, but I assume it's the same over here: when Mary pulls out a sheet, unfolds it, shakes it back and forth and then lets go, and the sheet takes the form of a bed that she sits on.
Actually, that whole scene was pretty amazing, especially since that entire set (the children's bedroom) was on a giant gantry and every nook and cranny seemed to be hiding a special effect. And it wasn't even the biggest part of the set!
The moment the opening music ends, those cymbals roll, and that scrim lifts to reveal the chain gang is still one of the most visually stunning images I've ever seen. I consider it an effect; the show has a very surreal look to it that never fails to surprise me, even though I've seen it many times. Love how the lights are of a golden, bluish variety of many shades/hues. Those brilliant, but earthy colors against the washed-out gray brick and cobblestone of John Napier's set, is magical.
Recreation of original John Cameron orchestration to "On My Own" by yours truly. Click player below to hear.