Hehe! I’m storing weather info for a great deal of my posts—no icons, yet—and have a “currently listening” sort of widget. (It’s just I never really listen to much anymore.) For the weather thing, I drew inspiration from the Simple Location plugin for WordPress. The music widget is just me polling my scrobble endpoint (also on my site, but I imagine you could use Last.fm just as well).
Remember how places like LiveJournal used to have "post flair"? They were effectively different emojis for your mood or the weather. I think there were even some music integrations so show the song you're listening to...I think I need that on my blog. Weather could be done free with OpenWeatherMap/weather-icons. Music might be trickier...