Where do I start? Okay, here's where I start:
The record-breaking performance of A Chorus Line. This review/description by Frank Rich will tell you why. I get goosebumps just reading about it.
Sarah Bernhardt as Hamlet. Because the one person who didn't say "Laurette Taylor in The Glass Menagerie" said "Sarah Bernhardt as Hamlet." I was 19; he was in his 90s; I felt connected to history.
Ethel Merman in Gypsy. Because, uh, it's Ethel Merman in Gypsy!
The original Follies. Could it possibly live up to the hype?
Arcadia at Lincoln Center with the original cast. Because I love Arcadia.
Arcadia in London with the original cast. Because I love Arcadia.
A Streetcar Named Desire in London with Rachel Weisz. Because I'm sure she was wonderful.
Penny Arcade with James Cagney and Joan Blondell in 1930. Because they're James Cagney and Joan Blondell.
Fred and Adele Astaire in anything! Was she really the better dancer?
Bill Bojangles Robinson in anything! Was he really the better dancer?
Edwin Booth as Hamlet. Would he seem hammy or wonderful or both?
Christine Sarry in Rodeo. Okay, it's ballet, not theatre, but I'd still love to go.
And then there are the shows I would see again (and again!):
Cloud Nine, first with the original cast and then when Michael Jeter was in it. I saw this show three times and would gladly see it once a year for the rest of my life.
A Little Night Music with the original cast. Another show I would gladly see once a year for the rest of my life (if not more often).
A Streetcar Named Desire with Rosemary Harris. Because she broke my heart.
Happy End with Meryl Streep and Christopher Lloyd. Because it was so much fun.
And I could go on and on and on.
(Do you suppose the time machine would have a TKTS booth?)