You've got your first personal 3D printer. You're excited to make things, and have already finished printing a few samples that came with the device. Now what?
Here's some ideas you might consider making:
Art: There is a surprising amount of fascinating artwork you can 3D print at home. While we don't know your artistic tastes, it's possible to browse online repositories to find objets d'art that may fit well on your desk.
Replacement Parts: That hook holding up the thing broke again. Rather than heading to the hardware store to re-purchase the entire unit again, perhaps you can 3D print a replacement part. At this time there are very few options for 3D models of arbitrary spare parts, but if you are handy with 3D modeling you might be able to create either a replica or alternative design that does the job.
Personalized Items: 3D prints today typically have poor finishes. They aren't shiny and often exhibit layering. What better way to distract from those deficiencies by personalizing the object? Simply paste a name on the 3D model and print it - the recipient (who matches the name) will be thrilled that something was made specifically for them.
Figurines: Inexpensive scanning solutions could permit you to create 3D models of your own face and body. Or someone else's, if you persuade them to hold still for a scan. Once you have these models you're free to 3D print as many of yourself and friends as you have plastic. Ok, we added the hat afterwards.
Impossible Objects: Have some fun shocking your pals by creating an "impossible object", something extraordinarily difficult to make using traditional techniques, but often trivial with 3D printing. A simple example could be a whistle - with the ball inside. Perhaps you'd like to print this bearing and "globe within a globe within a globe" shown here. They'll be puzzled until you reveal the secret method of its creation.