This is basically I Love You, Man Part Two. The "dinner" takes up only a fraction of the movie. Steve Carell shines as the neurotic IRS agent who's clueless when it comes to real life (which is kinda the point of the movie--that fantasy is better than real life). Anyway... if you want a few chuckles, you might want to catch this movie on a double-feature with any other comedy out right now. Otherwise, wait for the rental.
AC
P.S. Based on Carell's performance in this flick, I think he'd be a great choice for a Being There remake. No disrespect to Pete Sellers. I really think Carell could pull it off with the right director. Hmmmm....