The Suite Life of Zack & Cody became the 3rd Disney Channel series to crack the 65-episode barrier (after Kim Possible & That's So Raven), and also merited not a spin-off, but a sequel series!
Suite Life served as a showcase for twin brothers Cole & Dylan Sprouse ("Big Daddy"), who play Cody & Zack, respectively. Cody's the smart one, Zack, though 10 minutes older, is not quite as sharp, which would actually make him a match for heiress London Tipton (Brenda Song), who, despite her wealth, is a slacker when it comes to school.
The twins' mom, Carey (Kim Rhodes) is the hotel's resident chanteuse, which helps pay the rent on their suite, obviously. Early on, Cody had a crush on candy shop clerk Maddie (Ashley Tisdale, "High School Musical"), but that subplot went by the boards during the 2nd season, and Maddie was gradually written out of the series during season 3.
Following is the season 1 episode, "The Fairest of Them All":
After 3 seasons, Disney decided to move the series out of the hotel and out to sea, hence the sequel, The Suite Life on Deck. Rhodes & Tisdale were gone, and Debby Ryan was introduced as Cody's new girlfriend. On Deck also marked the series debut of Miller beer pitchman Windell Middlebrooks as a security guard aboard the S. S. Tipton. On Deck has also ended, and, currently, the Sprouses are doing some commercials of their own, for Dannon's Danimals brand of yogurt products for kids. Why Disney refused to put On Deck on ABC will never be explained, but it was a blown opportunity, to be sure.