I started collecting vintage playbills several years back and my most treasured ones are:
-- My Fair Lady OBC autographed by Andrews, Harrison, Lerner & Loewe
-- Original Pal Joey (1940) signed by Richard Rodgers
-- Porgy & Bess OBC (1935)
-- Hold on to your Hats (1940) signed by Al Jolson
Other items --
A letter signed by Jason Robert Brown, along with a copy of the then unpublished sheet music to "Come Up to My Office" from
Parade that included a few editorial notes.
A playbill from LaChiusa's "The Wild Party" signed by the entire cast
"You pile up enough tomorrows, and you'll find you are left with nothing but a lot of empty yesterdays. I don't know about you, but I'd like to make today worth remembering." --Harold Hill from The Music Man