We put together one of the toughest and least fun yet satisfying jigsaw puzzles I've ever done over the holidays. It's a thousand-piecer, but one of those "mystery story" ones so you don't have a picture to go by -- and it was a lot of brown and tan. It's called "Curse of the Feline Pharaoh" by Bepuzzled. Fortunately I found a picture of the completed puzzle on the internet, although only at a low resolution, at least it showed the layout of the basic components. I really like being able to pick up a random piece, go to the picture on the box, and say "Ah, yes, that is exactly where this piece will go." No way to do that with this baby -- even with a high resolution picture that wouldn't have worked for a lot of pieces -- the colors are too non-distinct.
Also fortunately, my parents came by for a couple days and pitched in, especially my mom who likes working jigsaws on occasion, and she pulled in my daughter, who doesn't like hard puzzles but likes working with Grandma. Here's a picture of some of us near to completing the puzzle; but I'm selling mine on Amazon.