What should I do when returning to minecraft?

I just started playing minecraft again yesterday after a lengthy break (let's call it 6 months, but it could be longer), and experience fell out of the coal I was mining. Then I found some iron ore and expected there to be experience in it...but there wasn't. First, what's the deal with that? Why is there experience in the coal?

Second, obviously things have changed a lot since the last time I played. Rather than spending days reading through the minecraft wiki, I was hoping a few people would give me some ideas of new things to do that I've never seen before. What kinds of new things should I do?

Thanks to anyone who posts. No need to upvote.