I don't have a huge amount to say about The Hangover as a lot of it would be fairly repetitive from what I have said about Old School and Due Date but here's the basics:
The Hangover is the, I-wonder-why-they-haven't-really-made-a-move-like-this-since-Bachelor-Party-it-seems-so-bleedin'-obvious!, lads go to Vegas and destroy everything film that is fairly funny and watchable if the above idea appeals to you in any way.
Zach Galifanakis is the stand out star because, quite literally, without his character in the film and if his character doesn't work then there isn't a film, Ed Helms is fine but a little one note and Bradley Cooper finally feels well cast in something after starring in absolutely every single film in the last two years.
A quick note about Heather Graham. In this she is reduced to playing a ridiculously stereotypical, unfunny and, quite frankly, boring stripper character, that's basically a cameo, and that may first come as a surprise, considering she was a name before any of the 3 'stars' of the film but you soon see why when it's glaringly apparent that she can't even act that right! She really is truly awful, I know she was never a huge star but this is ridiculously poor.
The first part of the film while they are setting up the premise, Zach G is the best thing in it because of his ability to say something completely ludicrous with a straight face whilst coming across as unhinged but harmless and the verbal comedy is my favourite bit, personally.
Once they wake up the next morning hungover and with a 'Fear and Loathing' amount of debris in their hotel room they start to put the pieces of the previous night back together and what follows are a series of revelations and high slapstick set pieces. Which are completely fine to begin with, the police station and the hospital scenes being the best as they are A) the most verbal B) the funniest and C) genuinely feel like they are putting a puzzle back into place, the whole Mike Tyson's tiger thing is a mildly funny diversion too but the sub plot with the baby, the stripper and the "hilarious" yet completely impossible wedding (you need a marriage license, even in Vegas you can't just waltz in drunk and marry anybody!) is predictable, cliche and fairly dull and the whole build up to the end with an Asian mob boss, that the film makers seem to feel is a lot funnier than he actually is, goes absolutely nowhere!
At a certain point the whole plot of the thing falls apart which leaves the ultimate reveal, of where the groom has been left, feeling underwhelming and the characters too, once clearly defined and funny are sanded down until, by the end, they are all just as good but as screwed up as each other, even Bradley Cooper's character who apparently hates his life at the beginning greets his wife with a big hug and a kiss at the end. It also feels like a completely wasted comical opportunity when the Ed Helms character finally breaks up with his nagging, controlling and downright horrible girlfriend because while it is, again, mildly hilarious, the potential was there, in better hands, for an absolutely hysterical ending.
So, while it may sound that I am knocking it, it is a perfectly acceptable comedy film, featuring just about everything you'd expect and a whole handful of stuff you wouldn't from a lads trash Vegas movie. Everyone but Miss Graham does their part perfectly well and it has a nice wrap up but none of it bares much scrutiny, has any hint of realism and isn't as funny as it could've been.

5.5 out of 10 big wobbly jellies that look a bit like breasts 'chuckle smirk'
Points from the Wife - 5 out of 10 Margarita's by the pool while the men piss about