TDF (formerly known as Theatre Development Fund) is a not-for-profit organization, dedicated to bringing the power of the performing arts to everyone by encouraging and enabling diverse audiences to attend live theater and dance. TDF lifts barriers to attendance whether they be financial, educational, developmental or cultural. They are best known for operating the TKTS discount ticket booths at Times Square's Duffy Square and in Lincoln Center's David Rubenstein Atrium. Additionally, TDF Accessibility Programs provides a free membership service for theatergoers who are hard of hearing or deaf; have low vision or are blind; who cannot climb stairs or who require aisle seating or wheelchair locations; or have families with children or adults on the autism spectrum.