Bill Murray really bowled three strikes in a row in the scene where his character, Ernie McCracken does the same. The crowd's reaction is genuine and is actually for Murray. Woody Harrelson, on the other hand, was a terrible bowler and according to the Farrelly brothers maybe got one or two strikes throughout the filming.
As is the case with most of his films, Bill Murray ad-libbed virtually every line he spoke. He would read over the script, get the general idea, and then discard it. The Farrelly brothers, on the DVD commentary, said that they're very glad he did, because it was funnier.
Peter Farrelly called the film's box-office failure the biggest disappointment of their career, attributing the failure to its release during the 1996 Olympics. Farrelly said that it was crushing. However, he said that six to eight months later, when the film was released on home video, it became a big hit.
In the scene before Roy gets his hand taken off, both Roy and Ernie enter a large building and begin walking up the stairs to the bowling alley. Roy asks, "People bowl here?" That is the actual location of the bowling alley where they filmed that scene, as it is located on the third floor of the building. The lanes are called Beaver Valley Bowl located in Rochester, Pennsylvania.
In the big bowling tournament at the end, an unseen person in the stands yells "Attaboy, Luther!". Everytime Don Knotts' character speaks in public in The Ghost and Mr. Chicken (1966), an unseen person also yells "Attaboy, Luther!".
According to the Farrelly brothers, they didn't initially take Lin Shaye seriously, after having already cast her in a small role in Dumb & Dumber at the suggestion of New Line Cinema studio executive Robert Shaye. However, when she came into read for Kingpin, she was mistaken for a homeless person looking for an ash tray. They politely tried getting her out until realizing it was her, in character, for the reading. The Farrellys were blown away and didn't see anyone else for the role. Shaye subsequently appeared in more of their films thereafter.
In the Cheers episode Cheers: From Beer to Eternity (1985) Woody Boyd, played by Woody Harrelson, reveals that he is an ex-bowling ace who retired due to crippling a man in a bowling accident. In this film his character is forced into retirement due to a bowling injury at the hands of Ernie McCracken.
Among others, Pro Bowling Hall of Famers Parker Bohn III and Mark Roth appear briefly during the final tournament scene. In one shot, Roy shakes Mark's hand after defeating him in a head-to-head match.
Major League Baseball pitcher Roger Clemens has a small cameo in the film. In the restaurant scene where Roy punches out Ishmael, Roger Clemens plays the part of Skid Mark. Clemens currently ranks eighth on the All Time wins list for Major League Baseball pitchers.
Throughout the movie Claudia (Vanessa Angel) and Roy (Woody Harrelson) refer to Ishmael (Randy Quaid) as "The Kid", even though Quaid is older than both Angel and Harrelson by sixteen and eleven years, respectively.
PGA Tour players Brad Faxon and Billy Andrade both appear in two scenes, when Roy enters the bowling alley in the opening sequence, and when he leaves for the first tournament. Both players have numerous wins on tour.
John Popper: lead singer and harmonica player for Blues Traveler, has a bit part as the announcer for the Reno bowling championship. Blues Traveler, in Amish garb, appears at the end of the movie playing one of their songs.
The trivia items below may give away important plot points.
In the scene in the bowling alley restaurant, just before Ishmael is about to get beaten up, the three are eating burgers and fries. However, Roy is eating a salad because actor Woody Harrelson is a vegan.