I know this doesn't neccessarily speak to the point because I'm not talking about Lucid's here, but, often after I've been doing something intensely during the day or even really thinking about it, it will bleed into my regular dreams. When I wake up, I will be better. It's interesting to think about. I noticed this when I was picking up tennis a few years back - I'd dream about playing and the following day I would be significantly better. I also get better at video games I've been playing after I dream about playing and then hop online on Live and wreak havoc. Good times!

However, some research says that sleep helps consolidate memories, and other research says it might serve to 'defrag' your memories, discarding the useless junk and either could probably go a ways to explain the phenomenon. An interesting experiment would be to introduce someone to an activity and have them practice it solely in their dreams and see how they perform after a certain duration.