Alstroemeria spp. or Peruvian lily
Well I think the picture says it all really why this should warrant a plant of the day spot. The flower above is most likely a result of interspecific crosses and lots of dedication and hard work. A shout out to the breeders! As noted below in Taxonomy I initially was abhorred by the length of the family name and then remembered that I've been seeing Alstroemeria in catalogs for a couple years now and it's not THAT hard to roll off the tongue.
Taxonomy: This is the type genus of the family Alstroemeriaceae or the Peruvian lily family. It is a relatively small family with only 4 genera but those 4 genera do give us about 200 species. Another really neat genus of this family is Bomarea which is a vine that produces some (often) very pretty showy flowers. The species Bomarea edulis has been used since pre-Columbian times as a food source (the tubers are edible).
ID: Well, you should be able to guess right off the bat that this puppy is a monocot, see those flower parts in 3? Not 6...3 :P. Well, the "roots" consist of a slender rhizome that forms larger "sausage like" structures that look a bit like thicker tubers. According to Wiki it looks a bit like a Dahlia. Comparing the pictures they are a bit different though, the "tuber" like structures on the Alstroemeria are not as tightly grouped as Dahlia.
I spoil you guys... anyways though so the rhizome on Alstroemeria is apparently a little dainty until ya consider its sausages. Felco shout out! If you bothered to make it this far this plant, and the family have an awesome and interesting characteristic. Resupinate leaves! Thanks to Wiki for have a link to resupinate. Fancy word for the leaves actually flipping upside down. Basically they twist at the base of the leaf so that what you see as the upper leaf surface is actually the bottom. If it weren't so damned late and I had more time I'd like to dig into why oh why it would do this, there is always a reason...
Culture: Most of the hybrids you'll run into originate from South American species. The only species note on MoBot's page for Alstroemeria aurea mentions that it is zone 7 hardy. Last winter, they would have lived in the ground most likely. They do like medium moisture well drained soils (like everything in the garden seemingly) and in our brutal summers I imagine they would appreciate afternoon shade or a part sun/dappled sunlight spot (this according to MoBot but I should think that sounds spot on...feel free to chime in Jason). They can be overwintered inside in containers or dug from the soil but again MoBot says the rhizomes are very brittle and hard to dig. Make sure not to water them.
There is much more I could share abou the ID and the culture and on and on...I recommend any avid gardener give this plant a look for the garden or perhaps to try as an indoor plant. What a lovely looking flower and there is a lot of information/stories about this plant to be found. It's a beaut. Did I mention they are really popular for cut flower arrangements? See...it never ends....ahhhhh!