The phrase "Y tu mama tambien", by itself, is not offensive, but if you put an offense before it or you answer to an offense with it, it is one of the most offensive phrases in Mexican Spanish. By itself, it means "And your mother too."
When the producers tried to buy the rights of Frank Zappa's "Watermelon in Easter Hay" they were told by Zappa's family that Zappa requested that three of his songs were never played in any media except the album where they appear and that song was one of them. Gail Zappa, Frank's widow, saw the movie when editing was almost completed and agreed to make an exception because she considered that Zappa would be proud of the movie.
The translation of the tagline is: "Life has its way of teaching us. Life has its way of confusing us. Life has its way of changing us. Life has its way of astonishing us. Life has its way of hurting us. Life has its way of curing us. Life has its way of inspiring us."
The last names of all the principal characters (Zapata, Iturbide, Carranza, etc.) are those of important figures in Mexican history. The last name of the one Spanish character - Cortés - is that of the Spanish conquistador who conquered much of Mexico for Spain.
The music video for Molotov's title song, "Here comes the Mayo", includes outtakes from the film, including scenes deleted from the theatrical release. These scenes are also available on the official webpage.
A poster of Ernesto "Che" Guevara can be seen in Saba's room earlier in the film when the boys are planning their road trip with Luisa. Gael Garcia Bernal, who plays Julio, would later go on to play Guevara in The Motorcycle Diaries (2004).