GIMP is the GNU Image Manipulation Program. It is a freely distributed piece of software suitable for such tasks as photo retouching, image composition and image authoring. It can be used as a simple paint program, an expert quality photo retouching program, an online batch processing system, a mass production image renderer, a image format converter, etc.
txt2pdf PRO is a very flexible and powerfu program that converts files from text to PDF format. It extends txt2pdf with features such as the ability to add form feeds, to skip the first form feed, to set the top and left margins, to use images (JPEGs) in the background, and to create compressed PDFs.
Unifdef is useful for removing #ifdef'ed lines from a file while otherwise leaving the file alone. You specify which symbols are defined or undefined with -D and -U flags, and unifdef removes the corresponding ifdefs, and the enclosed code if appropriate. It's especially useful for removing those "#ifdef BROKEN" and "#ifdef PRIVATE" clauses from code before you release it. Unifdef acts on #if, #ifdef, #ifndef, #elif, #else, and #endif lines, and it knows only enough about C and C++ to know when one of these is inactive because it is inside a comment or a single or double quote.
VICE is a Versatile Commodore Emulator, i.e. a program that runs on a Unix, Win32, MS-DOS, Mac OS X, Amiga, or RiscOS machine and executes programs intended for the old 8-bit Commodore computers. The current version emulates the C64, C128, VIC20, Plus4, C64-DTV, all the PETmodels, and the CBM-II (aka C610).