1. It is affordable
I hate the word affordable as it is usually used to describe $300 a night hotels, however in this case it is apt. TDF is the most well-known source for less expensive tickets. 20@$20 is great for certain Off-Broadway shows. Smaller theatre companies often have a pay what you can night, where they literally allow you to give as little as a penny. If you don't have the penny, volunteer. You can usher or do other work for all kinds of theatre in order to see the show; the Fringe Festival NY is famous for their volunteer program.
2. Small Theatre companies.
The Amoralists have always done interesting work and the Bats at The Flea continue to impress, season after season. I regret not seeing their Bible adaptation. These are not the places one goes to see Our Town revivals. This is interesting and often riveting work being done in these small venues.
3. Elizabeth Marvel and Annie Golden
I ran into Ms. Marvel the other day, some of you may not recognize her name, however the 'deconstructed' Streetcar that she performed in almost 15 years ago is still current and fresh in my mind. The moment I saw her, my head was filled with Shakespeare, Hedda Gabler, and at least a dozen other shows. Always visceral and completely memorable. A smart producer would give her Medea. Her ability to be both completely fragile and made of steel in the same moment is something to behold.
In movies the thrills come from the effects, in the theatre they come from the performers.
4. Theatre is now, it is only for the moment. Movies and TV shows can be seen on DVD, or screened through your computer. Much of our entertainment is on demand. Theatre is alive, it captivates moments in time. Being part of an audience is a unique and communal experience.
5. Anything can happen
Movies are the same every time you see them, you might notice something new but the film does not change. In the theatre people still talk about the night Patti Lupone (justifiably) went off on a rant against a cell phone user. Sets fall, lighting fails, and exquisite moments are captured in your mind to be savored for years.