Noun
flavor of the week (plural flavors of the week)
(idiomatic) A fad; someone or something that is held in esteem or receives attention for a short amount of time.
Synonyms: flavor of the month, today's flavor
When I wasn't the flavor of the week or month or day, those were hard times. Kiefer Sutherland
He's, I guess you could say, with all due respect, the flavor of the week because Herb Cain [sic] is the one up there who doesn't look like he's part of that permanent political class. Herb Cain - he came from a working-class family. He's had to make it on his own all these years. We respect that. Sarah Palin