An eight-song serenade is $200, but abuelita will cry when she hears "Cu-curru-cucu Paloma" or "Aquellos Ojos Verdes" played by four musicians with sombreros, ascots, trumpets, and gold-filigree suits. If her birthday happens to fall Monday through Thursday, the same set played by three musicians will only set you back $150, and the full song repertoire is available online. If mariachi serenatas aren't your thing, there are Brazilian, Columbian, and Peruvian bands; or romantic trios de bolero. Violinists, pianists, and harpists are available as well.