In an early scene, Rob Schneider attempts a golf drive by running up to the tee before swinging. Adam Sandler says, "That's the stupidest looking swing I've ever seen." This is a joke on Sandler's character's trademark golf swing in Happy Gilmore (1996).
Lucy is treated at the "Callahan Institute", which Dr. Keats (Dan Aykroyd) tells Lucy's family is funded by an automotive magnate, T.B. Callahan, out of Sandusky, Ohio. In Tommy Boy (1995), Chris Farley plays Thomas Callahan III, who runs an auto parts factory in Sandusky that's being threatened with foreclosure by Dan Aykroyd's character. Tommy Boy (1995) was also directed by Peter Segal.
The original script set the movie in Seattle, the hometown of scriptwriter George Wing.
Rob Schneider’s character Ula was inspired by Siope Samuela Ula Lomu, a Tongan concierge at a luxury rental property at which Schneider, Adam Sandler and Drew Barrymore are regular visitors. Lomu has the same blinded, grayed-over left eye that Schneider's Ula has, but there's not much resemblance beyond that. Says Lomu, "They aren't like some other top Hollywood people. They're really normal."
"Jocko" was played by Sivuqaq, one of four walruses living at Six Flags Marine World in Vallejo, CA. The three female walruses featured in the film are named Siku, Uquq and Qiluk.
When Henry and Lucy are first at his place they see two dolphins that Henry calls Mary-Kate and Ashley after the Olsen twins.
The book Lucy reads at breakfast, "Still Life With Woodpecker - A Sort Of A Love Story" by Tom Robbins, is a love story set in Hawaii.
The neurological condition that Lucy suffers from, Goldfield Syndrome, is entirely fictional. True anterograde amnesia affects either short-term memory, which can last minutes or seconds, or intermediate-term memory, which can last days or weeks. Falling asleep has nothing to do with the condition, and sleep actually intensifies many chemical effects which help memory.
In an early scene a dentist and a woman in the dentist's chair are seen talking with each other. The woman playing the dentist is Jackie Sandler, Adam Sandler's wife. And the woman in the chair is played by Linda Segal, director Peter Segal's wife, who actually is a dentist in real life.
Originally entitled "50 First Kisses".
Henry makes a video for Lucy to remind her of the events that have occurred since her accident. One of the items is "Red Sox win the World Series...” followed by "... Just Kidding". During the year of the film's release, the Red Sox actually broke an 86-year drought and won the World Series. 'Drew Barrymore' made the movie Fever Pitch (2005) about an avid Red Sox fan and they filmed the final scene on the Busch Stadium field while the Red Sox celebrated winning the 2004 World Series.
Actor/Producer Anthony Begonia was set to play a cameo as an ukulele player but was unavailable.
In the first scene where Henry walks into the Hukilau Cafe', Nick can be seen wearing a gray greasy tank top with the "W Y" logo of the Weyland-Yutani company from the Alien movies.
The Cafe that they keep meeting at is actually a house they fixed up for the movie. It is located on a macademia nut farm on the eastern side of Oahu. The same house was used in Tears of the Sun (2003). And they also filmed scenes from Jurassic Park (1993) in the open fields nearby.