My pal Sime is doing a nice thing at the BBC for the Springwatch programme.
When you're out on your Sunday afternoon walk and you spot the first snowdrop of the year, or hear the first cuckoo, you can text in what you've seen and add it to a map showing the progress of Spring across the country South to North. (It's using some sort of cell ID location to get a rough idea of where you are.)
Everyone likes it when the evenings start getting lighter, and marking the first time you notice Spring for yourself by doing something - sending a little text message butterfly off into the air - seems a really sweet and fun thing to be able to do.