ServerCobra writes: "Last week, Mark Pilgrim pulled down his popular Dive Into.. sites. I remirrored a couple of them, because they are far to helpful and important to lose. DiveIntoPython.net, DiveIntoPython3.net, and DiveIntoHTML5.net."
Every nonzero finite dimensional inner product space has an orthonormal basis. It makes sense, when you don't think about it.