Imagine what they could have done with a million dollars in books, art supplies, lab equipment, musical instruments, ...

No, I don't think so. More likely they already own outrageous capacity to handle the December retail crunch but don't use anything close to that capacity in any other month of the year. So I doubt there's any additional investment in capacity for EC2. EC2 utilizes what Amazon already owns.

If you read Werner's blog entry on this new feature you'll see they reserve the right to interrupt a Spot Instance and essentially restart it later on. You need to make sure whatever you're doing with that instance you can checkpoint and resume. I think that means Amazon is not trying to "fire sale" underutilized resource. More like they're filling in the cracks between larger "full price" instances in order to maximize utilization.

According to the OLPC wiki the concept is more than simply giving computers to children "to somehow make them learn more." Instead they write: "While the technical aspects create a platform for change, the real benefits will come from improved educational practice enabled by immersive access to connected laptops." So, no claim that simply giving children laptops lets schools off the hook.

The OLPC advances an idea (to me somewhat orthogonal to basic educational practice) that connecting laptops connects the students together in ways that gives rise to other beneficial effects. Since we're all sitting here reading Slashdot it's an easy analogy -- Slashdot creates a community with a shared common interest, but with diverse opinions on those interests, and at the end of the day it's that diversity that is of interest. We read to learn what others think. So OLPC (ought to) create a means for children to interact with other children with the same effect, but on many other topics besides "news for nerds." And that sounds like a fine idea to me.