Patrick Page, Tobey Maguire and Lukas Haas at The Glass Menagerie (the Tiffany revival). Later saw Matt Bomer and Andrew Rannells leave out the stage door as well.
Charlie Cox leaving out the stage door after A View from the Bridge
Steven Michael Quezada leaving the stage door after All the Way
Finn Wittrock (or a look alike) at Blackbird.
Zeljko Ivanek at The Harvest at Lincoln Center
James Franco at Angels in America on a marathon Saturday. Tony Kushner was on the opposite end of the row from me as well.
Barry Manilow at Come From Away; Irene Sankoff and David Hein were there that night as well.
Hugh Jackman and his wife at Three Tall Women.
Last October, I was in town for Comic-Con and on a break I saw a pretty good non-premium orchestra seat for Hello Dolly was available, so I decided to skip The Walking Dead panel at MSG to see Dolly instead. I was the second seat off the aisle and the woman in the aisle seat was there when I arrived, and I paid no attention as she allowed me past to sit. She got up a minute later to say hello to someone she knew, and the people seated in front of me asked if I recognized her, then it must've clicked for them and they said it was Marcia Cross. I looked, and sure enough it was. I'm not one to initiate conversations with strangers randomly so after she returned I didn't say anything, but she ended up asking me if I just bought my tickets last-minute and we made a little small talk before the show began. Afterwards, she asked if I was happy with my decision to see HD instead of going to TWD panel, I told her I was and we parted ways. I never brought up her work or otherwise acknowledged knowing who she was, though on the way out one half of the couple in front of us complimented her work. Across the aisle, Annette Bening was at the show that evening as well.