Update: Fallon and the Roots have answered

Justin Timberlake and his band on tour The Tennessee Kids accepted the ALS Ice Bucket Challenge.

He Challenged Jimmy Fallon and The Roots to do it next. Which gives them 24 hours to donate at least $100 or dump an ice bucket over their head. 

You can donate to ALS without dumping ice on your head here: http://alsa.org/donate/.