"... I can't always just drop whatever project I'm currently working on and start doing "cool new stuff". I have responsibilities and commitments to my adviser and my colleagues. ..."

There is a great section on "Surely you're joking, Mr. Feynman" with Feynman describing burnout. From what I took from this was play as such wasn't time out from commitments but a different way of approaching problems. If you get bored it's a chore but if you play it's not. Read this extract (pg. 157-158) to understand ~ http://pages.swcp.com/pcaskey/feynman.html