I love colored pencils. They're soothing and you can draw pretty things with them without the potential of staining your shirt. I remember seeing this necklace making the rounds on Pinterest a bit ago and being smitten. While this DIY project (pictured) from Design Mom isn't the exact same thing, it's close enough! You'll need some tools (sandpaper, drill, mini hacksaw) and a moderate amount of elbow grease, but look at the result -- Cutesville: Population, This Necklace.
For those of you who don't want to bother with the "DIY" part, you can buy something similar, like this one from Etsy. (You can tell your friends you made it, we won't tell.)