Fast Sunday in our religion is the first Sunday of the month that is set aside for the members to fast (go without food for 24 hrs) for a purpose/need. We also, after taking the sacrament at church that Sunday, do not have any talks/sermons. Instead, the members have the opportunity to bear their testimony to the congregation.
Here's a conversation that happened last Sunday as we were getting ready for church:
Jackson to John: "Dad, is today Fast Sunday?"
John: "Nope, today is not Fast Sunday. That was last week."
Jackson: "Oh.... so today is just a slow sunday?"
Love that kid :)