Holy RAD! I'm going to go out on a limb here and say the only thing more Nerdily Awesome than a ukulele made out of Legos would be be playing strip Dungeons and Dragons with Princess Leia (wearing her slave costume, of course). So, since that's probably never going to happen for you, at least the Lego ukulele thing in still real.
Head over to Makezine to learn more about these little slice of radness. And, if you aren't already a subscriber, you should consider it. It's easily my favorite magazine in the world. I think there have been 2-3 articles on how to make your own cigar box guitar as well as all sorts of bitchin' electronics howtos. If you have nerdy leanings and you aren't already reading this magazine then you should be ashamed of yourself. 😉