Episode four of “The Singer and the Song” is devoted to “Tequila.”  Released into the world as catchy little rock instrumental in 1958, that song’s astonishing elasticity over the last six decades has generated flavorful jazz, r&b, rap, ska, cumbia, movie soundtrack, and marching band versions by notable performers including Pee Wee Herman, Joeski Love, and Wes Montgomery and by lesser known devotees including Perez Prado, Los Bitchos, Ska Cubano, the Reverend Horton Heat, and the University of Washington’s Husky Marching Band.  Drink up!