Whos Playing Tonight is a free iPhone app developed by Jack Gruber. It falls under the lifestyle category and aims to make it easier for users to find out who is playing at jazz venues in NYC, DC, and Baltimore. With this app, users can see listings from multiple venues in one place, eliminating the need to visit multiple websites. The app provides daily updates to ensure users never miss a great show. Whether you're looking for a specific artist like Kurt Rosenwinkel or want to know who's playing at a particular venue, Whos Playing Tonight has you covered. It's a must-have app for jazz enthusiasts who want to stay up to date with the vibrant music scene in these cities.