We all use free open-source software to run our printers and design the things we print. Please remember to say “thank you” (or flattr / make a small donation) to the developers who dedicate their free time to these awesome projects.
My thanks go out to (including, but not limited to, in no particular order):
Erik Zalm with the Marlin Firmware: https://github.com/ErikZalm/Marlin
Kliment with the Sprinter Firmware and Printrun: https://github.com/kliment/Sprinter , https://github.com/kliment/Printrun
@Gina_Haussge with @OctoPrint : http://octoprint.org/
@Daid_Braam with Cura: https://github.com/daid/Cura
@Alessandro_Ranellucc with Slic3r: http://slic3r.org/
@Roland_Littwin with the Repetier Host and matching Firmware: http://www.repetier.com/
@Mark_Moissette_ckaos with CoffeeSCAD: http://coffeescad.net/
Please let me know if i forgot someone!