What are some more things to do with an FPGA? One Instructables user, krosenfeld7, made a guide for an FPGA composer.

This Instructable is a guide through the design and construction of an electric keyboard/composer. A composer functions like a piano– when a key is pressed, a corresponding note is played. The composer is constructed of a Nexys 2 board connected to a speaker. Once everything is going, you can play different notes and create a new song!