I somehow missed when Yongnuo announced six months ago that they would begin making lenses for Nikon cameras. They recently gave a quick preview of the first offering.
Yongnuo is a Chinese company that's been making camera flashes for a little while now. They recently entered the lens market, making a couple of Canon-compatible prime lenses. These lenses are super cheap (one is under $60 and the other is under $125), yet seem to perform at least as good, if not better, than their name-brand rivals.
The first Nikon-compatible lens that Yongnuo will make is a 50mm AF-S f/1.8. It looks just like the Canon-mount 50mm f/1.8 that Yongnuo began selling last year, so I'm wondering if it is the same lens, just with a Nikon mount. Rumor has it, although I found nothing concrete to confirm it, that the next lens after the 50mm will be a 35mm AF-S f/2 (which is what the other Canon-compatible lens is).
There has been no word yet on when Yongnuo will make the 50mm lens available or how much it will cost. If I were to guess, I'd say that it will be released in the fall and sell for under $75. For the price, it seems well worth a look.