UPDATE: I added a new version "boo_supported.stl" that is designed to be printed at a 45 degree angle and has built in supports. With a well tuned printer this will result in the best quality for all faces. Give it a shot! The printed version in the photo was done this way.
Just a simple text decoration that says "Boo!" in a fun design. Designed to stand up as block letters. Print on the front face for a smooth finish.