It was the song "Cielito Lindo", performed by Desi Arnaz.
"Cielito Lindo" (Gorgeous Sky) is a popular ranchera song written in 1882 by Quirino Mendoza y Cortés. With research suggesting its origins in the Iberian Peninsula in Mexico, the lyrics are an unofficial anthem about romance.
This song had multifaceted life. It was also interpreted by Pedro Infante in the movie Los tres García (The Three Garcías, 1947) and was jointly sung by the three tenors Placido Domingo, Luciano Pavarotti and José Carreras in 2006
If you're in the mood to move your hips to salsa or samba, or just want an evening's entertainment watching talented dancers boogey to hot horns, here's a list of films to watch shared by About.com.