reprap

Slic3r is Nicer - Part 1 - Settings and Extruder Calibration provides good tips for calibrating and configuring 3D printers.

PhysibleExchange - Popular. Another place where you can find 3D models for 3D printing. This one has some really practical things, not just toys.

Cura. This would be software that can make the printing process more efficient - an all-in-one package with integrated model preview, slicing, printing and all kinds of parameters. And also available across systems (which I am always excited about: almost all software in this area is available across systems).

3ders.org - Infographic: step-by-step guide for 3D printing with a RepRap. Nice little overview of what all needs to happen for 3D printing. Certainly, some of this can be made more efficient with the right software choice, but in one form or another, everything is involved.

Printable wood available. Cool - printable wood. Basically just a wood powder-plastic mixture that can be processed like normal wood after printing.

Tinkercad - Mind to design in minutes. Wow. There's even 3D design software for 3D printers that runs completely in the web. Okay, since you can boot Linux in the browser, nothing should surprise me anymore, but it's still cool ...

repetier/Repetier-Host-Mac · GitHub. And the necessary software to control the printer.

RepRap - RepRapWiki. Well, this will probably soon become important reading for me. Pretty cool stuff, 3D printing.