Laura's on Worldchanging!
I'm probably going to get pelted by her for this, including spending hours every week during her hectic final semester at college riding a bus to and from MIT to make org meetings, not to mention working round-the-clock to keep everyone sane, fed, organized, and happy (and spending long hours defusing discussions and organizing volunteers, to boot).
And now she's going to Zambia for D-Lab. Actually, she's probably already on her way there to save the world (which is probably the only reason I'm able to write this in the first place...) Definitely one of those people you have to keep an eye on, since you have no idea what she's going to do in the next 10 years but you know it's going to be spectacular.