In order to open the door to Jerry's pick-up, he has Lindsay lift the handle while he kicks the door from the inside. When they return from their date to the tar pits, Lindsay simply opens the door using the outside handle, but does not have to kick or push to open it.
In the scene where the van is pulled over for 37 MPH on the freeway Robert Brown's seat-belt goes on and off between cuts.
In the opening credits when Jerry spills coffee on himself several coffee grounds are stuck to his face. They vanish and reappear through the scene.
The coffee stain on Jerry's "Happy Camper" shirt vanishes when he pulls up to Ozzie's place, then reappears in later scenes.
The call letters of the station for the announcer in the finals taking place in California starts with a "W" (WKXP). Broadcasting call letters in the USA west of the Mississippi river start with a "K". However, this was not standardized until the 1930s and many stations created before that time kept their W or K even though they were east/west of the Mississippi.
When the grill "falls over" in the backyard scene you can see that a hole has been dug below one leg, as it falls into it as soon as Jerry lets go of the handle.
(Possibly deliberate) When Jerry pulls into the gym parking lot and comes to a stop under the street lamp, the truck brake lights do not function.
Driving to the regionals in Phoenix the fighters go through a McDonalds drive-thru. Ozzy passes out the food and calls out the items one by one which includes onion rings. McDonalds does not sell onion rings.