PyMP3Cut is a Python command line tool designed to cut huge (> 100MB) MP3 files at high speed without requiring the extra disk space and processing time usually needed by visual audio editing tools, which convert the MP3 format to more easily manageable formats like WAV before doing anything. It reads and cuts simultaneously according to the autodetected MP3 frame rate and a timeline passed as a command line argument. It doesn't currently deal with Variable Bit Rate (VBR) MP3 files, though.
Real pdf editor. You can use either many already present script functions, or you can create your own, or you can use low level object tree with knowledge of pdf specification to do almost everything with your pdf.
Tiger is an emulator for the TI92 - a powerful calculator from Texas Instruments. It's written entirely in C, using the 68k-emulation routines from UAE, the fameous Amiga emulator. You will always need a real ROM-dump from the TI92 to run it.