I used to belong to the website where members do the RAKs, I did a few myself and it was great fun. They normally do them on Fridays, or did. One day I went into a shop and bought a box of Thornton's chocolates, went to the till and paid for them then turned to the woman bhind me waiting to be served and asked her if she liked chocolates, she said yes so I told her they were for her and walked out of the shop.
Another Friday I bought two bunches of flowers and put one each on the desks of two of my colleagues, much to their surprise.
I belong to a forum where we all make greetings cards, if someone is unwell (not just a cold) or has been having a tough time we do card showers for them and they receive cards from all over the world over the space of a couple of weeks. That didn't seem quite fair somehow as some people would never qualify for a card shower so we also have a random shower each month, the receipient knows nothing about it until the cards begin to arrive. I just mailed one off this morning, and in fact one yesterday too, one to a person who has been having a tough time and the other the random one.