The Virtual Electronics Library, or VE-Lib, is a C++ library used to easily add electronic simulation in your programs. It makes use of the scripting language Lua to easily add new components like new resistors and microchips.
tile breakout boards on a printed circuit board
Breakout boards _can_ be made by cutting off a piece of circuit board and going through the etching, drilling, solder-resist and printing process, but doing this for multiple boards quickly becomes tedious, especially if you've got to make more than a few. With v3c-eagle-tile, you can import several CadSoft Eagle .brd files and tile them onto whatever size pcb you have to hand, process them all at once and cut them apart when you're done.