Flavorwire crafted this video montage of some of the trippiest movies ever made:

Films (in order of appearance): The Trip (1967, Roger Corman), Head (1968, Bob Rafelson), Glaze of Cathexis (1990, Stan Brakhage), Allegro Non Troppo (1976, Bruno Bozzetto), Natural Born Killers (1994, Oliver Stone), Fantasia (1940, Armstrong, Algar, et. al), 2001: A Space Odyssey (1968, Stanley Kubrick), Viva La Muerte (1971, Fernando Arrabal), The Holy Mountain (1973, Alejandro Jodorowsky), Performance (1970, Donald Cammell and Nicholas Roeg), Videodrome (1983, David Cronenberg), Dark City (1998, Alex Proyas), Belle De Jour (1967, Luis Buñuel), Eraserhead (1977, David Lynch), El Topo (1970, Alejandro Jodorowsky), Tetsouro, the Iron Man (1989, Shin’ya Tsukamoto), Inland Empire (2006, David Lynch), Dead Alive (1992, Peter Jackson), Waking Life (2001, Richard Linklater), Anchorman (2004, Adam McKay), Mulholland Dr. (2001, David Lynch), Un Chien Andalou (1929, Luis Buñuel), Requiem for a Dream (2000, Darren Aronofsky), Lost Highway (1997, David Lynch), Pi (1998, Darren Aronofsky), Easy Rider (1969, Dennis Hopper), The Big Lebowski (1998, Joel Coen), Naked Lunch (1991, David Cronenberg), Skidoo (1968, Otto Preminger), Being John Malkovich (1999, Spike Jonze).

What no Sweet Movie? (Runs away).