Do something beautiful
I'd love to hear of some of the random acts of kindness that people have tried out from that site.
In the meantime, here's one that I know works with friends.
It's actually borrowed from our friends in Albania who, either out of the neccessity of not being able to afford much phone credit (despite all having mobiles!?) or from being quite inventive, or both, use an unanswered ring in a simple but effective way.
Whilst sometimes ringing and hanging up straight away might be used to signal "I'm leaving home now" for a pre-arranged meeting, it is often used simply to indicate "I'm thinking about you right now."
What a simple and powerful way to make someone's day, having previously told them what it means. Where so often (in my experience) a single ring is used as a nag for "why haven't you replied to my txt?", instead it becomes something to cheer up, to beam a thought or to send an e-hug.
Too sentimental? Have you gone soft Matt? Try it, you'll see!