Donating to this particular cause is easy. They have a website that links directly to a place where you can give any amount of money. They have the challenge that started a huge chain reaction and got people who probably wouldn't donate otherwise to do so.
Instead of being critical of it, maybe you should try to be more like it.
Just so you know, this post started about an hour ago as one that was talking about how I think the challenge is dumb and how I agreed with the "slacktivism" article. The more I thought about it, though, the less I agreed.
I'm still not going to dump a bucket of ice-water on my head...Instead, I'm going to participate in an event that honors veterans, volunteer at a triathlon, and work to do things that make the world I live in a better place.
Get involved. Work hard. Donate if you can. Volunteer if you can. Participate in food drives/clothing drives. Pick up that piece of trash you passed by in the parking lot and toss it in the trash. Recycle. Give to Toys for Tots. Join the military. Feed the missionaries or a starving college student ;)