Chris Farley and David Spade don't just have great on-screen chemistry, they were actually very close friends in real life and this is probably why neither one of them were terribly capable of achieving much on their own.
Tommy Callahan III (Chris Farley) barely graduates from college and returns to his hometown to accept an executive position at Callahan autoparts. A position he clearly does not deserve and does not have the mental fortitude to handle. Tommy is assigned his father's assistant Richard Hayden (David Spade) to help him settle in at the company.
Tommy's father, "Big Tom," tragically dies at his own wedding and now the company has to be handed down to his good-natured, but rather dumb son "Tommy Boy." There are financial problems with the company and the banks are very reticent to provide any additional funding in the absence of Tom Sr. at the helm. The only way that they will loan the money to Callahan Autoparts is if they manage to sell 500,000 sets of brake pads within a certain time frame. Thus begins Tommy and Richard's quest across the country to a string of sales meetings.
What makes this movie great is that Farley and Spade work so well together and the fact that one of them is fat and dumb and the other is skinny and clever, make their interactions with one another even better. Most of the comedy is quite juvenile, but this isn't exactly a film that would be submitted in Cannes.
anyway, i laughed a lot and if you are like me you might as well.
The downside of this film is that Farley being a uncoordinated oaf with good intentions kind of wears off after a while and there really isn't much more to his and Spade's humor than that. It takes me longer than others to get sick of this, but I can understand why some people wouldn't really like a film that is basically a 1.5 hour SNL skit. This movie did reasonably well at the box office but not great.