I have a interest in interfacing and programming TI graphing calculators. I own a
TI-89, and am interested in programming ti as well as interfacing to it.
Right now I am involved in decoding the protocol used
to communicate with the ti-89, which is being documented piece by piece.
The best source of information for all TI graphing calculators is TICalc.org. They serve as a repository for
calculator programs (with an emphasis on games) and information.