This paper presents E-Chalk, a software system which transforms a large touch sensitive screen into a smart teaching tool. The instructor writes on the screen using a special stylus and the software emulates a classical chalkboard. The lecturer can paste images to the board, can send queries to remote web services, can activate a computer algebra system, and can paste interactive Java Applets on the board. A copy of the lecture’s audio, the board strokes (and an optional video) is stored on a server. The lecture is also transmitted live over the Internet and can be synchronized with teleconferencing systems for student feedback. The E-Chalk architecture is based on the metaphor of the classical chalkboard, enhanced by intelligent assistants running in the background. One assistant takes care of interpreting the handwritten input of the user. Another is a mathematical formula recognizer which processes handwritten queries for the algebraic server. A circuit simulator recognizes sketches of digital circuits and runs a simulation. An algorithm simulator accepts sketches of graphs as input data and runs graph algorithms, animating them on the screen. Further assistants can be incorporated using the E-Chalk API. E-Chalk is being used in our electronic classroom containing a 6 meter long by 1.15 meter wide rear projection “data wall”.