1. "The History Boys" (2004) by Alan Bennett: This play, set in a British school, explores themes of education, identity, and class. It received critical acclaim and numerous accolades, including the Tony Award for Best Play.
2. "Doubt: A Parable" (2004) by John Patrick Shanley: This Pulitzer Prize-winning play delves into complex moral dilemmas and explores the themes of doubt and faith. It was also adapted into a critically acclaimed film in 2008.
3. "The Curious Incident of the Dog in the Night-Time" (2012) by Simon Stephens: Based on Mark Haddon's novel of the same name, this play follows the journey of a young boy with Asperger's syndrome as he investigates a mysterious incident in his neighborhood. It won multiple awards, including the Tony Award for Best Play.
4. "Hamilton" (2015) by Lin-Manuel Miranda: This groundbreaking musical combines hip-hop, R&B, and traditional theater to tell the story of American Founding Father Alexander Hamilton. It became a cultural phenomenon, winning numerous awards, including 11 Tony Awards, and had a significant impact on Broadway and popular culture.
5. "The Humans" (2016) by Stephen Karam: This Pulitzer Prize-winning play follows a dysfunctional family gathering on Thanksgiving, exploring themes of family relationships, immigration, and the American dream.
6. "Harry Potter and the Cursed Child" (2016) by Jack Thorne, J.K. Rowling, and John Tiffany: This two-part play is a continuation of the beloved Harry Potter series, set many years after the conclusion of the original books. It achieved commercial and critical success, breaking box office records in London and on Broadway.
7. "The Lehman Trilogy" (2018) by Stefano Massini, adapted by Ben Power: This epic play tells the story of the Lehman Brothers investment bank, chronicling its rise and fall over the course of three generations. It received critical acclaim and won several awards, including the Tony Award for Best Play.
The "best" play is ultimately a matter of individual opinion, and many other excellent and influential plays could also be included on this list.