With the Jonas Brothers' half-hour Disney Channel show (debuting in May '09), expect brand-new music, guest stars (Big Rob! ''Bonus Jonas'' Frankie!), and major high jinks. ''We're trying to cook Mom a special birthday cake,'' explains oldest sibling Kevin, 20, who's wielding the fire extinguisher as Joe and Nick look on. ''We destroyed our family's home videos, so we have to find ways to make up those memories.'' From the looks of it, mission accomplished.