On 9/13/13, at a Target in Plantation Florida, I paid for a gentleman's two cases of water. The cashier rang them up under my name and I just had a good feeling about this guy, so I said I'll go ahead and pick up the tab. He was exceptionally grateful and had an expression of shock and gratitude. Remembering this thought still brings me feelings of joy. Definitely worth doing no matter the price of the other person's item!
i tipped a waitress 300% of the bill because she was awesome, and was having a bad day. Counting it because I was paying my good day forward, which is the essence of this one, if not exactly what I was going for.
I kind of did this when our ward went to the Manti pageant on June 24, 2011.
I asked one of the ladies volunteering there where to get ice cream. She said she didn't know, but that she'd love a chocolate ice cream cone. So I bought one and brought it back to her.