This movie was quite funny. I though it was a very nice addition to the franchise. I gave it three and a half stars because there where some things in the story that where never concluded, and the description leads you to believe that Gaylord is gearing up to have children when he in fact already has twins.
Mostly the movie surrounds the twins fifth birthday and the father in law wanting to continue the family legacy through Gaylord. This bring him to looking into a very expensive private school for his kids and taking some unusual risks that involve Jessica Alba selling "Boner medicine."
In this movie you will see Robert Deniro having a five hour hard on and Ben stiller giving him an adrenaline shot for it, Owen Wilson getting a tattoo of Gaylord's wife on his back followed by him falling off a poll doing some crazy acrobatic performance then also being followed by him kissing Gaylord's mom, Jessica Alba popping to many pills and mixing them with Wine, and Dustin Hoffman "mastering" Flamenco dancing in Spain. Plus much more funny stuff.