Ideas on how to use the 3D printer (hopefully not destroying anything in the process)

At the near beginning of this class I started to work with the little knowledge I had to create something for my sister who had just found out that my class had a 3D printer. She is a big fan of Doctor Who so I started to work on a Tardis, finishing it in just 3 days. It still has a lot of little things to fix so it can be printed but I have the core and idea of the box down.

Many of my friends have also requested things for me to make like things from shows they like such as Sailor Moon :

I would like to see If I could model some sort of action figure that is positionable or all the joints move.