User blog comment:Mobo85/Phineas and Ferb Goes Fourth/@comment-2156322-20111110004223

"Upcoming episodes include a musical featuring the one-hit wonder "Phineas and the Ferb-tones," commemoration of Platypus Day, and a winter vacation special featuring seasonal sports and a New Year's celebration."

So Much for the One-Hit wonder back in '08. I suspect the Winter Sports episode will be in Jaunary 2014, to concide with the Winter Olympics than next month.