My super-fast, Little Green Pallet Christmas Tree:
First, I started with a standard US pallet 40"x 48". Then, I started cutting from the bottom inside the runner to the top, then the opposite side with a circular saw. Next, I cut off the back slats inside each runner. I sanded the rough edges and any splintery bits, but left some of the rustic pallet texture. Then, I applied a cheery green paint and let it dry. Finally, we got some cheery lights, hung some ornaments, and topped it off with a fun little star on a spring.
For variations, you could make a hinged, folding leg, similar to a picture frame to prop it up anywhere you wanted. Perhaps, you'd prefer to put a hanger on it so you could mount it on the wall. Finally, you could create a set of feet to allow it to sit indoors or out. We just leaned it up against a bench for the time being.