People suspected it in The Dukes of Hazzard, and Employee of the Month confirms it - Jessica Simpson cannot act.  She has a great voice, and a greater body, which the movie shows off often with a series of tight, low-cut shirts and sweaters.  But her acting ability is minimal at best, often wooden and unemotional.  Simpson delivers her lines with a minimum of emotion, often looking uncomfortable and stiff.  Thankfully, she doesn't have many stretches that require her to say more than one sentence at a time, but the result is still a deadening thud.  Simpson kills every scene she is in, sucking any sense of life out of it.  Her co-star, Dane Cook (London, Waiting...) fares much better.  Cook sprang to stardom using MySpace to promote himself as a stand-up comedian.  Although he's had small roles in other films, this is his first starring role.

How does he do?  Well, he's okay.  Nothing particularly impressive emerges.  Cook doesn't come across as anything special.  But a large part of this is due to Don Calame, Chris Conroy, and Greg Coolidge (Sorority Boys), who came up with the story and the script.  Employee of the Month is a comedy that isn't funny, with a small romance that isn't romantic.  It takes an idea (a lazy guy and his friends working at Costco) then beats it to death.  Cook is Zach Bradley, a Costco employee for the past decade.  He and his slacker friends are happy as box boys, the "lowest of the low" in the employee hierarchy.  They sit around and waste time, and generally get by in life.  Until the arrival of Amy (Simpson), who, Zach learns has a thing for the Employee of the Month.

Unfortunately for Zach, he is not a model employee.  This role belongs to Vince (Dax Shephard, Idiocracy, Zathura), a preening cashier who lords his superiority over everybody.  Vince has been Employee of the Month a record 17 times, and if he wins it one more time, he also wins a brand new car.  Vince also sets out to woo Amy (albeit badly), and a battle for Amy and the title ensues with Zach.  Like every story of this nature, the easygoing, loyal Zach forgets his friends as he begins to win Amy and as he escalates his juvenile war with Vince.

Employee of the Month drags on even as it tries to pace itself quicker.  Each day has a winner, and at the end of the month, the person with the most days wins.  Vince takes a bit more then the first week.  Then Coolidge (who also directed) has to slow things down so that there can be more of a contest between the two guys.  Zach needs to slowly learn how to be a better employee, woo Amy, and in between there are all sorts of pranks, some amusing and some not.  But Zach is too much of a nice guy, Amy too hot, and Vince too arrogant.  Everybody comes off as extremely fake, so by the time the movie reaches its climax, nobody cares anymore.