Ask HN: Graduation Present for Aspiring Math Major?

One of my wife's piano students is going off to college, and the student wants to major in math, at a liberal arts college with a strong mathematics department. As we are invited to her high school graduation party, I thought we ought to bring a gift along, and I'm wondering what you suggest as a gift to send someone off to college as a math major. I can think of a few books, but perhaps you have some other ideas. Any and all hacker-friendly suggestions welcome. Her dad is an MIT-trained engineer and has run a start-up business for a number of years, so I figured this was the right place to ask this question.

A blackboard for his room.

For books i'd suggest Men of Mathematics that has inspired countless people to math careers or Terence Tao's Solving Mathematical Problems, which is excellent.

Now, if money's no object, i.e. you're willing to spend around $200, the gomboc (http://en.wikipedia.org/wiki/Gömböc) is a wonderful object to buy, you can buy it at the gomboc-shop.com

Well, I said blackboard because we're talking about a potential math major and I'm pretty sure a majority of mathematicians prefer blackboard and chalk.

Something from Grand Illusions might be fitting: http://www.grand-illusions.com/acatalog/

Lots of interesting / nerdy gifts, including some math related: http://www.grand-illusions.com/acatalog/Maths_Toys.html

Feynman is great choice too. "Surely you're joking mr Feynman" is a classic.