Once upon a time, my first boyfriend was playing Tim Algood, in Noises Off.  During a production, one of the flats on the set fell down.  Without missing a line, he grabbed some nails from backstage, and proceeded to tack the flat back up.  Of course, the audience had NO clue.

Short play written by a local playwright. I hadn't read the script, but was sitting in on a rehearsal to give my opinion to a fellow director.

One of the actors was using a strange speech impedement and said the line..."My husband and I used to go to Zabars"

I could have sworn she said "My husband and I used to go to Gay Bars"

The speech impedement was changed slightly going forward. :)

During a production of Robin Hood a couple years ago, Robin is confronted by "Death" personified in the forest and it's a relatively intense moment, where "Death" is convincing Robin to go turn him self in, to his death, in order to save Marian and etc. 

Someone back stage knocked into the bowls and dishes that were stacked for the Merry Men's encampment so there's a nice clatter.  As I watched from the booth, I thought the two actors were just going to ignore it, but Death turned around and looked off stage in the direction.  Thank god Robin was a quick thinker "Oh, that's my men... they've gone off that way."

On closing night, two actors got together and decided to mess with the actress playing Marian... she's talking with her father and he's very surprised to see her in junky clothes and smelling like the pig stie and he asks if the outlaws have ravished her and inserted an "Eee gads, they haven't gotten you pregnant?"  Marian took it in stride with a "NO, Daddy!"  What she didn't know was that later in the next scene when she returned to Prince John to make demands on him over the state of the outlaws, he *also* inquired about her being pregnant.

Pregnancy joke came back this past year when the Marian actress paticipated in our Improv comedy night.  They were doing a game where each performer would in turn come onto the scene and be accused by another performer based on a single given line that they then had to build a scene around.  The Marian actress came into the "room" and was accosted by the performer already there with "Jenny called, who's Jenny?"  And they started going at it and it eventually evolved into that Jenny was from Planned Parenthood!  This wasn't even (to my knowledge) ever an intentional continuation of the pregnancy gag, but a great fluke.


Last year's production of Get Smart, we encouraged them to ad lib a bit in order to develop their characters more - some very very funny stuff happened. 

The Chief was supposed to do a speech during black-out and we opted instead to do it live in his office as part of the scene, but he started working with his secretary and adlibbing a much longer sequence where he's lost the memo only to have his secretary find it in the desk drawers that he didn't realize he had!

Another Chief/secretary gag was that we'd covered his desk with hundreds of papers to add clutter and add to his stress levels.  The poor secretary (who played Marian in the above example!) would pick up the handful of papers that would fall off occasionally.  As we kept going night after night, the Gadget Guy would come in and start knocking more and more papers off that she'd have to pick-up.  Closing night, after she'd cleaned up and exited the stage, the trio of actors had plotted to knock the papers off the desk again and make the secretary actress come back on stage to pick up the pages!  She was soooo not happy.   Later in the play during her final exit of the show, she was about to leave in the custody of the agents when the Chief called her attention over, held up a single sheet of paper and very deliberatly dropped the single page onto the ground.  Got a huge laugh!  She came out with a sheet of paper and ripped it in half on her curtain call.   (It was actually my suggestion later that they should have made yet another pregnancy pun at an appropriate moment earlier in the show, but it was after closing that I thought of it)

One actor had a voice-over as a radio announcer and went into this elaborate thing about the station's sponsors being Orville and Redanbacker, etc. 

There was another scene where the same actor as a different voice-over was presenting ransom demands including a million dollars in fives, tens, and a few singles.  Well, on our second night he added in: "fives, tens, twos, and a few singles."  (requiring an adlib by the Chief of "I could never get such a sum, not even the two dollar bills!")  And continued to elaborate in his Russian accent about how quote (from the video files) "I swear on my little dog, thug the pug who chews on her bone every night as she comes to bed and always chews on and brings to my lap which she always offers in exchange for some of the popcorn I'm eating that she always leaves all over the bedspread, that I will kill you if there aren't any two dollar bills or singles."

Originally posted by neilfortin In A Funny Thing Happened on the way to the forum...Domina's line about her father "General Magnus" turned into General Viagra one night...and people LOVED it. (It helped that our director had placed a very naughty freize of general magnus...with a rather large  SPEAR above her house!)

Great piece of Up or Downstaging!