Now it seems they're coming by regular mail! I received this today in our company's PO box:
It's got a real "signature" on it, (you can see the pen indentations on the reverse side of the page) and it's postmarked from Spain. I have no idea how they would have got my name - the address I can see, because our company website has all that info, and they could've just found that at random, but even my company email address only has my first initial and last name, so it's a bit weird they got both names associated with the address. Funny they got my first name spelled right (even with the "e", rather than the more standard "a") but not my last name.
Anyway, I know some people like to play with these folks, so if anyone wants to, have at it. I blurred my name out because I know these things tend to get around the net (and I hope it does!).