I went to see Dinner for Schmucks last night and I absolutely hated it. I want that two hours of my life back. A supposed comedy, the movie was really an enormous goof of the sad life of a guy who had some mental health issues. Yeah, I know, it's fiction, it's not supposed to be taken seriously, etc. I get the premise, but the mistake the movie made was showing just how sad the Steve Carell character's life was in the midst of all the goofing. The movie made the Carell character all too real, which made the humiliation all the more difficult to watch.
If you don't have anyone in your family/life/circle who suffers from mental health challenges, you will probably find this movie reasonably funny. If you do though, you very well may walk away like I did, feeling somehow kind of dirty for participating in the whole process.
I do not recommend this movie. Go and see Sly Stallone blow stuff up instead.