Some I've heard over the years:
"Aida" instead of "Dance of the Robe"
"Ruprecht" instead of "All About Ruprecht" (even I'm guilty of that one...)
"Do No Harm/The Yodel Song/the Doctor song"...anything except "Ruffhousin' mit Shuffhausen"
"Great Big Stuff Reprise" instead of "Son of Great Big Stuff"
"I Got The Horse Right Here" instead of "Fugue for Tinhorns"
"I Only Want To Say," or "What if I Die" leaving out "Gesthemane"
"No Day But Today" instead of "Life Support"
"Art Isn't Easy" instead of "Putting It Together"
"If there was a Mount Rushmore for Broadway scores, "West Side Story" would be front and center. It snaps, it crackles it pops! It surges with a roar, its energy and sheer life undiminished by the years" - NYPost reviewer Elisabeth Vincentelli