Jimmy Fallon is the latest celebrity to participate in the ice bucket challenge, the frat bro approach to charity that’s sweeping social media. On the “Tonight Show” Wednesday night, Justin Timberlake challenged Fallon to dump a bucket of ice water over his head to help raise money for ALS. Fallon, along with Rob Riggins, The Roots, Steve Higgins, and Horatio Sanz, met the challenge and passed it on to the New York Jets. And so it continues.