You have just a few minutes.  Usually even less than that.  If you want to make a video more interesting, you can use a multi camera (multi cam) shot.  Slow motion is also a good choice, especially with an "event" like the ice bucket challenge.  Don't have software to edit multi cam?  Just place the clips one after the other and play the event twice.

A few other ideas include:

• Borrowing styles from pop culture (in this case, the TV show 24)
• Using memes are also catchy
• Give a first person view of the event if possible and if it won't damage your gear
• A moving camera creates interest.  I used an aerial right but you could arguably accomplish the same shot with a smart phone (and have less noise).  I just happened to have one lying around and couldn't help myself 

Ice Bucket - Multicam from Keith Twitchel on Vimeo.