Large 7 or 14 segment LED display, with optional colons and dots.
Default STL files are 150mm (~6") tall, with a 10 degree slant. You might want to rotate them 100 degrees after import (90 degrees + your chosen slant value) to best align on a Makerbot / Clone style bed.
Defaults are sized height wise to fit into a 1" deep art frame, such as these: http://www.dickblick.com/products/blick-metal-gallery-frames/
These print 'upside down'. Once done printing, flip them over and screw them to the mounting surface.
They are mostly hollow, so infill and other settings don't really matter.