I usually never go see war movies, unless it's Sci-Fi or a comedy. Tropic Thunder definitely falls in the later category. Very funny movie, starring Ben Stiller, Jack Black & Robert Downey Jr. Three different actors, but they work great together. Nick Nolte, Brandon T. Jackson and Jay Baruchel also have a strong presence and Tom Cruise has a fairly short role, but it's much more then a cameo. Talking of cameos, there are many short ones in this movie, so don't blink!
I laughed a lot during this movie. It's about actors that are sent in a jungle to experience more realistic conditions of war, so they can better understand their roles. Of course, they get stuck in a much more real war then they intended. It's a movie within a movie type of scenario at the begining, but 'their' movie is no longer going on, until the end of 'our' movie, but they think they are, at least most of them... Did I lose you? Many very funny situations, some of them a bit controversial in real life, but let's face it: Who would expect a politically correct story from this?
Regarding Tom Cruise, you have never seen him like this, I guarantee you that! Actually, with the heavy makeup, he's hardly recognizable. If I didn't knew he was playing that character, I just might have not noticed he was in the movie until I would have seen his name in the credits.
There is some violence, but mostly in a humourous way, of course, strong language and mature subjects. Not a family movie, you have been warned. But if you are mature (at least legally), like to laugh and haven't seen it yet, I think you will enjoy Tropic Thunder.