I would wager that most geeks out there spent lots of time building things when they were kids. I know I used to build all sorts of things from Lego, Tinker Toys, and Lincoln Logs. I still build stuff on occasion with my son out of Lego. A new set of building materials for geeks has debuted called Nanodots.
The little spheres are strong magnets and look like BB's to me. Each of the beads is magnetized and they will stick together in any shape you can imagine. You can get the beads in four different colors including original (nickel), black, silver, and gold colors.
Each set of the beads comes with 216 little balls, a carry pouch, and an instruction manual with building tips. Pricing varies with the color with the cheapest being the original color at $29.99 per set and going to $39.99 per set for the gold Nanodots. You need a bunch of these if you want to get into complex shapes; some designs have over a thousand Nanodots.