Kids pick up languages much faster than adults.
I took French in high school and college but barely remember any of it - yet I remember all the words to a Christmas song I learned in German in 3rd grade. Songs work, games work, especially if they can relate them to the English version, and if they know how to read English there are some biligual children's books, too. If there are cartoon video rentals in Spanish with characters they know, that would be fun for them. Kids pick up languages much faster than adults. I took French in high school and college but barely remember any of it - yet I remember all the words to a Christmas song I learned in German in 3rd grade.