in 1964, they released their hit album k-39. the title track became a big hit and is one of their best known songs. the group continued their successful career, recording several albums a year, shocking by today's "one album every two years" pattern. they also had their own tv show called "surf's up!" hosted by stan richards in '65-66 and appeared frequently on another dance show called "hollywood a go-go" hosted by sam riddle in '65-66. saxophonist phil pruden left the group starting with the release of "california kicks" in 1966 making the challengers a four piece guitar driven group for the remainder of their run. during this time the group and surf music popularity overseas in japan and other countries was exploding. this led to the creation of four more groups with members from the challengers. the surfriders, the good guys, the clee-shays and the de-fenders all produced albums for these foreign markets.