One of the first rules of comedy is that everything immediately becomes funnier when an old person does it—like rapping, skateboarding, trying to live a life of quiet dignity, etc. Also, starring in The Hangover, whose time-tested comic formula of “dudes having a wild party” must reasonably be improved by a factor of 10 if those dudes are also old, according to the standards of Hollywood math. "They're old dogs! And they're playing poker!" [Runs screaming to buy 20,000 movie tickets.]
And thus we have Last Vegas, a film whose sole purpose is to get elder statesmen of acting like Michael Douglas, Robert De Niro, Kevin Kline, and Morgan Freeman into a wild Las Vegas bachelor party, then laugh at the incongruity of their doing shots, hanging with LMFAO, and offering cholesterol medication to strippers. (Ha ha, old man, that is definitely not the kind of “drugs” they are looking for!) Anyway, for what it’s worth, the simplicity of the premise definitely lowers expectations to the point where this could easily surprise us, and all involved seem to be having fun—particularly Morgan Freeman, whose Red Bull-and-vodka-fueled ramble at trailer’s end at least gives you the chance to hear God drunk off his ass.