If you don't have plans to see this movie, you can check the spoilers here and then come back.
I was highly anticipating this movie from the trailers and talent involved when it came out in theaters, but then never managed to see it and it didn't make much of a splash so I forgot about it. I'm glad I decided to check it out at home, because this was a very solid, very funny effort that distinguishes itself from the ever burgeoning genre of (let's call them) vulgar stoner comedies quite nicely. The primary strength of the film is the contrast between Danny McBride's enthused ridiculousness in the face of the setting to James Franco's earnest embrace of his straight man role as it's a microcosm of everything that works. This isn't a full-on send-up of the swords and sorcery genre in the way, say, Robin Hood: Men in Tights or things along those lines were, but in many ways a medieval adventure story that's 60% serious and well-crafted as such so that it's more funny the way the comedic aspects stick out. Because the technical aspects of the film are so well done from the sets to the effects to the battle sequences, the casual crudity of the lines coming out of McBride's mouth in his ridiculous accent make you laugh more, and when Franco occasionally breaks from his decrees of nobility or lovelorn poetry to swear, it's even better. Having Natalie Portman take her role absolutely serious in the midst of the absurdity is perfect, as is having Charles Dance essentially playing Tywin Lannister with not a hint of irony. Justin Theroux hems and haws a bit in his role as a creepy and sexually repressed sorcerer, but he hits more than he misses; if anybody is underutilized, it's Zooey Deschanel, if only because they set up a nice recurring gag with her early on and then drop it after a few scenes. I would say that even at under two hours this isn't a long movie, but too long for this particular premise by just a little bit. It's not just a funny movie, though, it's a movie that's comedy is clever and calculated, despite being mostly sex jokes and curse words, and achievement in and of itself.