How to save without really realizing it

Recently, during a meeting of a business networking group I belong to that meets over breakfast a couple times per month, one of the group's members shared this really neat tip for saving up money for, well, whatever - some sort of goal, a rainy day, a trip, etc. At the end of each day, she goes through her purse/wallet and any other place where change is left over from the day, and she'll put any $5 bills she finds away. Some days, obviously, she won't have any to tuck away, but many days she'll easily find at least one. What a cool idea, I immediately thought when I heard it. What a clever way to save for something without making it a big burden and dramatically impacting your lifestyle. Thought it was a tip certainly worth sharing here.