The various outlets that sell Off Broadway Tickets and Off Off Broadway tickets.
Telecharge and Ticketmaster handle 95% of Broadway show ticketing, making the question "Where do I buy my Broadway show tickets?" a fairly simple one to answer. However, getting tickets for the hundreds of other theatrical events throughout New York City can be more complicated. It helps if you know a little bit about which companies process ticket sales for Off-Broadway, Off-Off-Broadway, and other non-Broadway shows.
Although Telecharge and Ticketmaster do handle some Off-Broadway ticketing as well, a large number of the Off-Broadway musicals and plays are handled instead by two other major ticketing services, Ticket Central and TheaterMania/Ovation Tix. A very small number of Off-Broadway shows do ticketing through SmartTix. Many theater companies don't use any of these ticket services at all, preferring instead to do ticket sales using their own online ticketing mechanism and in-house phone number for taking orders. In those cases, you'll want to go directly to the Off-Broadway theater company's website to find out about getting tickets.
The primary ticketing services used by Off-Off Broadway shows and events are the above-mentioned SmartTix, Ticket Central, and TheaterMania/OvationTix, with Off-Off Broadway tickets for a few shows being sold through smaller alternative services like Tix.com, TicketWeb, and the promising upstart Brown Paper Tickets.
Because Off-Off Broadway shows are usually short runs and operating on very low budgets, many of them opt to handle their own ticket sales (it's not at all unusual for the ticket "hotline" to actually be the cell phone number of the show's director or producer!).
Below is an overview of the available Off-Broadway and Off-Off Broadway ticketing services that sell, promote and supply tickets to Off Broadway and Off Off Broadway Shows.
Telecharge.com and Ticketmaster.com
These behemoth ticket sellers mostly handle Broadway show tickets, but they also sell tickets for some Off-Broadway shows. Telecharge, which is owned by the Shubert Organization and almost exclusively dedicated to theater ticketing, sells far more Off-Broadway and Off-Off Broadway show tickets than Ticketmaster does.
This ticketing agent sells tickets for numerous Off- and Off-Off Broadway plays, musicals, and special events. In addition to web and phone ordering options, Ticket Central also has an office in midtown New York City (at the Playwrights Horizons building at 416 W. 42nd Street) where you can buy your Off-Broadway tickets and Off-Off Broadway tickets in person.
TheaterMania / OvationTix
TheaterMania.com is another major ticket seller for Off- and Off-Off Broadway shows and performance events. Some of the ticketing is done through their website under their own name, and some of it is done under the name OvationTix.
SmartTix specializes in Off-Off Broadway ticketing, as well as ticketing for music, dance, comedy, and even some film events.
Tix.com and TicketWeb.com
These ticketing services haven't caught on big with the New York City theater scene yet, but they do handle tickets for a few Off-Off Broadway shows and special events around the city.
Billed as a "fair-trade ticketing service," Brown Paper Tickets is a newer company aiming to alleviate customer frustration at the increasingly obscene ticket surcharge prices by charging a reasonable per-ticket handling fee (what a concept!). They sell a small number of Off-Off Broadway tickets.