A really simple flute that's quick to print. It's open ended, but hold your finger over the end when you blow into it, and you'll get a loud noise.
You can also use this model to tune the minimum time per layer you can print (under slic3r's Filament -> Cooling tab, default is 15). I have a fan, and I've printed it with 4 seconds per layer, and it came out fine. With those settings, the flute took 15 minutes to print.
No support should be necessary. Remember to look at the output gcode and scale it up or down as necessary to avoid infill on the round sections, it should only need 2 perimeters. With my 0.35 nozzle, I can scale it to 90% to avoid all infill.
The flute in the picture was printed with a brim, but that was a mistake. No brim has been necessary.