For my 3D Printer Reviews at http://nicklievendag.com I've printed an army of Yoda Busts over the past months - you probably have a few yourself as well!
So I decided to print him a Christmas Hat!
It's designed to be printed in two colors with a single extruder 3D printer.
Depending on your printer, temperature and material, you might need to print the hat at 101% to make it fit nicely.
Most printers allow you to pause the print process manually, switch filament, and resume printing.
Some printers allow you to pre-program a pause height. I used this technique (Pause @Zpos) on the ZYYX I Reviewed on http://nicklievendag.com/zyyx-3d-printer-review-part-1. For the 100% version with raft I set the pause height at 12.4 mm.
You will need to print supports, but only for the inside of the hat - the arch on the outside doesn't need support (set your overhang angle so they're not generated there).
Depending on your printer, you might need to use a Raft to increase adhesion for the little white ball.
You might need to print this very slowly to print the bottom half of the little white ball nicely.