I have a package of programs which calculate the cohomology of modules over the Steenrod algebra. Input and most output consists of text, with a little bit of pdf output. The tools are command line (Unix shell scripts and C programs).
I want to add a web interface. I have a very crude prototype that could quickly be improved to a minimal functional version. I have in mind a much more beautiful, graphical version as well, which I would love to see implemented.
The programs as they exist are useful to a number of people in the field, but with a good graphical interface, they would be much more widely used.