ete Frates, a onetime captain of Boston College's varsity baseball team, is credited with starting the challenge. He was 27 when doctors told him in March 2012 that he had ALS, a progressive neurological disease that slowly robs those afflicted of the use of their muscles. At the time of his diagnosis, Frates was still belting home runs on a semi-pro team in his native Massachusetts. Today, he is confined to a wheelchair and uses a feeding tube because he is no longer able to swallow.

An active advocate for ALS awareness through the philanthropic fund that bears his name, Frates organized several charity baseball games; a fitting idea considering one of the game's all-time greats, Lou Gehrig, died from the disease. But it was when he dared some of his friends to dunk ice water over their heads in the name of ALS awareness that things really took off.

Continued, and here's Sidney Crosby doing the challenge:

And you can visit the ALS Association's website here.