Here's an award for the open source community art tunnel Modular Art Pods. Host a MAPs in your town. Learn more at http://www.modularartpods.com.
Print without support structures. The four squares on the corners are brims to prevent the sides from curling. Remove when finished.
I recommend a layer height of .2mm and nozzle diameter of .4mm. The pieces snap together. Make sure your printer is well calibrated.