Philadelphia has the oldest continuously operating theater in America. Let that land for a second. Walnut Street Theatre opened in 1809 - older than Abraham Lincoln, older than the railroads, older than the entire American West - and it's still running a full subscription season of drama, musicals, and classics. Walking into the Walnut is walking into American theater history, and the productions hold up to the setting.
The Broad Street Belt
The Kimmel Cultural Campus on Broad Street is the downtown performing arts anchor - a complex that includes the Verizon Hall (home of the Philadelphia Orchestra, one of the five great American orchestras), the Merriam Theater for Broadway touring shows, and the Perelman Theater for smaller productions. The Philadelphia Orchestra's program at Verizon Hall is worth attending even if orchestral music isn't your default - the acoustics are among the best in the country and the ensemble earns its reputation every week.
Across Broad, the Academy of Music is the oldest opera house in the country still being used for its original purpose. Full Italian-style grandeur: horseshoe tiers, ornate plasterwork, a chandelier that somehow makes the room look even more like 1857. Pennsylvania Ballet and Opera Philadelphia both perform here.
The Commercial Strip
The Forrest Theatre on Walnut Street handles the larger Broadway touring productions that need 1,800 seats to be financially viable. Reliable, well-programmed, and the Walnut Street pre-show dining corridor is a full evening on its own.
The Comedy Ladder
Helium on Sansom Street is one of the sharper stand-up rooms on the East Coast - serious booking, purpose-built room, and the two-drink minimum is a feature not a bug. Philly Improv Theater (PHIT) on Broad Street does long-form improv and sketch with a performance schedule that keeps the room active all week. Good Good Comedy Theatre in Callowhill is the indie alternative - smaller, weirder, and consistently discovering new voices before they get famous. Start at Helium for a headliner, graduate to Good Good for the discovery. Grab tickets on Evil Tickets and work the full ladder.