I will second Glengarry Glenn Ross.
I nominate the first play in Tom Stoppard's Coast of Utopia trilogy, Voyage.
http://en.wikipedia.org/wiki/The_Coast_of_Utopia
The Coast of Utopia trilogy is about the philosophical debates in prerevolutionary Russia between 1833 and 1866.
The ebook is available from Kobo and Amazon for $7.99.