A new experience can offer exactly the change of perspective you need to stimulate new ideas. Do something out of the ordinary to get out of your routine and provide inspiration. For instance, if you live in the city, plan a camping weekend for a change of pace. For inspiration, look to motivational speakers by attending lectures or watching TED talks. Check the websites for local universities to see listing of scheduled lectures that might provide you with the proper inspiration. Visit www.TED.com/talks to browse a large library of motivational talks by topic. Music can complement your brainstorming sessions, or be the inspiration for your ideas in and of itself. Try to listen to a wide range of music to vary your musical experience (e.g. if you're a fan of classic rock, make an effort to listen to jazz or R&B music for a new experience). Look online or in local newspapers for concerts or smaller performances near you.
Do something out of the ordinary. Watch lectures. Experience music.