Aside from Marvin, there are a bunch of other prints that will help optimize your 3D printer and get a better understanding of its different settings. While these calibration tests will likely be frustrating, they will ultimately help take your printing to the next level.
Benchy
http://www.thingiverse.com/thing:763622
What it tests: Surface Features / Resolution , Warping, Overhangs, First Layer Problems
Tips: Creative Tools already posted a Talk thread on Benchy and would be the best person to ask!
https://www.3dhubs.com/talk/thread/jolly-side-calibrating-3d-printers
Overhang Test
https://www.thingiverse.com/thing:58218
This object is used to test and calibrate better overhangs with relatively flat angles. It’s designed to test angles from 20° to 70° with increments of 5°. There are angle marks at the top of the object.
What it tests: Overhangs!
Tips: Increase or decrease by 5 degrees to see the difference. Slow down the print speed to let the parts cool between layers.
Torture Test
http://www.thingiverse.com/thing:33902
What it tests: Corners, layer alignment, overhangs, holes, and basically everything hard about 3D printing
Tips: A lot of trial and error. 15-20% infill, no supports, and a willingness to experiment
Temperature Test
http://www.thingiverse.com/thing:696093
What it tests: The optimal temperature for that particular filament, Gcode is optimized for Ultimaker
Tips: No real tips here, just pick the one that looks the best to you.
As many of you know, each printer has its own personality and these are not absolute tips, but more of a direction to to get you started tinkering. If you have any other prints that you regularly use to calibrate your printer, feel free to share!