Here's a little taste:
DJ Stout, partner, Pentagram: "Do self-assigned or 'not-for-pay' projects. Anything that doesn't involve a 'real' paying client who will most likely reject or rip the heart out of a truly original or innovative idea. For instance, I've been doing silk-screened posters for a creative speaking event called Pecha Kucha and I've been doing little self-published books on things that interest me."
Loni Peristere, founding partner, Zoic Studios: "Replace yourself. The intern program at Zoic is loaded with young super creatives. Their inexperience with production and process often opens the doors for huge ideas. We also hired a number of industry veterans of 30 years or more across the art and production divisions. These legends also bring amazing solutions. How do you keep sharp? Surround yourself with people who will call you out when you are dull."
Thanks to AdAge for the constant inspiration!