While the solutions already submitted are fantastic if you want to get it legitimately, there is a much easier method for those of us without morals.
If starting from scratch or to preserve your current world:
If you don't give a fig:
* Go to a vacant lot, choose "Create New Household to Move In"
* Create the new Sim.
* Go back to the lot on your most recently created Sim. Click on lot, and go left two icons to "Build".
* Go to Objects by Function. Note that where your monetary details would be normally is an infinity symbol.
* Go to Activities and Skills, then Creative. Find the object "The Virtuoso Violin" for 15,000 simoleons.
* Put down about 70 of the suckers. On the account I verified this with, I wrote out ROSEBUD using 5x7 letters just to be cute.
* Save. Return to Manage Worlds.
* Go to your violin-laden plot. Press play. Let it load. Receive Achievement.
Do not attempt to do this with a Sim you've already played with, as building edits will cost simoleons.
Instead of creating a new Sim to work with, you can also use a prebuilt family. I prefer the new Sim method because it's a lot easier hitting Bulldoze when you're done instead of individually selling however many violins individually. Unless you really hate the BFFs, then do your worst.