This site was founded by and run by Wendy @ Caribousmom for many years and has now been passed on.
DEFINITIONS:
Challenges - Usually set up over an extended period of time which encourages participants to read a certain number of books or type of book; can be for a set period of time (with a beginning and ending) or may be perpetual (with no time limit).
Events - One time book related happening, OR weekly memes, OR book related events such as read-a-longs or read-a-thons or annual happenings which may be scheduled for short periods of time.