I concur with all previous posters who already cited: 70 Girls 70 Anyone Can Whistle Chess Cry For Us All Dear World Do I Hear a Waltz? Do Re Mi Flora, the Red Menace Goldilocks I Had a Ball It's a Bird, It's a Plane, It's Superman Jane Eyre (saw it) Merrily We Roll Along (saw it) Passion (saw it) Prettybelle (I was shocked by how much I loved it) Rags Seesaw (attended opening night) Side Show Smile (saw it several times) Taboo Tenderloin The Apple Tree The Grass Harp The Secret Garden (that wasn't a hit?) The Wild Party (both) Zorba as you can see, I only saw a few of those, but wish I had seen all...
and for me the best of those fine scores are: Candide House of Flowers Mack & Mabel Parade
and I'd like to add: A New Brain – highly recommended!!! Celebration Grind Kwamina Runaways (saw it – talk about a mess!) The Nervous Set
I was lucky enough to see Carmelina in previews. Basically the same plot as Mamma Mia! (based on 'Buona Sera, Mrs. Campbell'). Was not thoroughly impressed (I think I don't like most musicals that take place in villages -- or what I call "the Joesph Stein musical" of which this was, methinks. Remember thinking Georgia Brown was quite good, and lots of lovely music at times. I didn't think it would close so quickly.
Love me my Rockabye Hamlet and glad to see there are two other fans. Also King of Hearts Wildcat Prettybelle Subways I Can Get It for You Wholesale. (300 perfs and I think a financial flop, but not sure. ) Really there are so many wonderful scores that are forgotten.
I've never considered Ragtime a flop, given its prominence in musical theater circles, but it had an absolutely amazing score.
My personal fav flop (discounting Ragtime) is Chess. It's not perfect, but I saw a production of it at Signature Theater in Arlington, Virginia and I was floored. With the right adjustments, it could rock Broadway - songs like Nobody's Side, Anthem, and Pity the Child have become showcase favorites, so it has the built-in fanbase.