The "polar plunge" (into an icy body of water) has been used as a fundraising tool for a number of charities and this seems to be a spin-off of that - the Cold Water Challenge or Ice Bucket Challenge. It's been used for several different causes but for the past few months is mostly associated with ALS. It's pretty simple: agree to have a bucket of ice water dumped on your head with the act is recorded (to post on social media) or otherwise make a monetary donation to the charity.
Is it a good idea? Well there has been a huge jump in both funds raised and in awareness for ALS in the past couple of months. Former president George W. Bush completed the challenge. So did NBC's Matt Lauer. According to The New York Times, ALS Association "received $41.8 million in donations from July 29 until August 21. More than 739,000 new donors have given money to the association, which is more than double the $19.4 million in total contributions the association received during the year that ended January 31, 2013." The ALS Association even has a special page on their website now (HERE) that deals with the ice bucket challenge.
It might seem silly, but when you can draw attention to a disease and make more folks aware of it, that is certainly a good thing and raising money for a worthy cause is always a good thing. Yes, there is controversy, but one way around that is to just go right to the source. Give directly to ALS - as much as you are able, and find out for yourself about the disease. Then share your information with others.