Oh, I love printing things inside things (especially if they rattle and move), without assembly! This is a simple design: Rotated bands cut from a hallow sphere form a sphere, and another one inside. Madness! Daily earring prologue: http://thingiverse.com/thing:7120 ~2cm/0.8" diameter on UP+, see image for print settings. Printing it 45° rotated reduces support material (the other version broke when I tried to remove support).Perhaps printing it with a lower support angle setting will speed up the cleaning process, but it may result in even rougher edges. Coloring with nail polish will take care of that, as usual.