This was Director Gareth Carrivick's final production. He died of leukemia the 16th of March 2010, less than a year after the movie was released in the UK.
When Pete is in the restroom he lifts his sunglasses and looks at his watch exactly like the poster and DVD cover for Back to the Future (1985). Michael J. Fox is in the exact same pose.
As the three main characters leave the cinema there are three posters shown behind them: "A Boys Life" (the original title of E.T. the Extra-Terrestrial (1982)), "Watch The Skies" (the original title for Close Encounters of the Third Kind (1977)) and "Paradox" (working title for Back to the Future Part II (1989)).
When Ray first meets Cassie, she is wearing a necklace with a butterfly. This is possibly a nod to one of the most famous time travel short stories, "A Sound of Thunder" by Ray Bradbury, where a time traveler changes the future (his present) by stepping on a butterfly in the distant past.
One of the most famous time travel short stories, "A Sound of Thunder" by Ray Bradbury, where a time traveler changes the future (his present) by stepping on a butterfly in the distant past, is referenced during a discussion of the "rules" of time travel when Toby says "You can't tread on any butterflies."