annoyme is a program that plays a sound effect every time you hit a key on your keyboard to give you the feeling you are using a real typewriter. This can be used to impress colleagues with your typing skills or just for sentimental reasons. It supports various sound input methods, as well as multiple output libraries like ALSA or AO. Most importantly, it is also possible to add more sound themes. Currently, only input for XEvIE (on an X Server) is supported.
KMidimon monitors events coming from a MIDI external port or application via the ALSA sequencer, or Standard MIDI Files. It is especially useful if you want to debug MIDI software or your MIDI setup. It features a nice graphical user interface, customizable event filters and sequencer parameters, support for all MIDI messages and some ALSA messages, MIDI playback, and saving the recorded event list to a text file or SMF.