Happy Birthday(s)

[atomictangerine.livejournal.com]

My mom's birthday is coming up. I never know what to get her-- or my brother, whose birthday is the same day as hers (as are the birthdays of two close friends, and yet another relative-- all on the same day! Fortunately I already have gifts for the rest of them). They're both such minimalists. I thought maybe my mom would like some simple yet elegant jewelry. Still not sure about my brother...
After much deliberation, I made my mom these earrings:



So, all set for Mom-- but that brings me to the question part of my post. Do any of you crafty ladies have ideas for a "geeky/science-y" kind of craft? My brother is a mathematician, so anything that's somehow math-related might be neat, as well as anything related to physics, science in general, or classical music. Normally coming up with things to make as gifts is so easy for me, but this time I'm just stuck!