I find myself keeping notes at work of ideas I'd like to flesh out try next time I'm in front of my gear. I rarely actually carry them out but it's a fun exercise while I'm at work. Sometimes I think it just makes me feel like I've created something when I haven't, though, and that I would be better off just not writing any of this stuff down and saving my creative energy for when I'm in the lab.
How about you? Do you have a perpetually growing list of ideas that you take cues from? Do you like to keep your mind as clear and open as possible when you jam? Somewhere in-between?