Make a point to set a day and go shoot something you have never shot before. If you are a sports guy go and shoot some landscapes- if you are a portrait guy go find and airshow- you get the idea.
I try to take my camera with me when I leave the house. I even keep it by the door so I remember.
The "assignment" threads are fun, and kind of force you to "get out there".
I like Jeff's idea - try something different than usual. Or maybe something altogether new.
I'm feeling it too, actually - lots of grey, rainy, cold days here still, which kind of crimp my motivation. I've done some indoor stuff but am not too happy with the results (and don't enjoy it nearly as much as outside). I'm not happy with some of the outdoor stuff I've done, either, so I have to redo them when conditions are right. Riding out the learning curve I'm on is keeping me busy, but gets a little discouraging at the same time. I think it will be easier when the weather gets better. (Note to self - winter not a great time to buy new camera.)
Another photog friend and I schedule a day to go out every month or so. Sometimes we go out shooting. Sometimes we take the laptops down to Panera and brainstorm biz stuff. Yesterday we went out and just went exploring. We found a handful of awesome locations for sessions. We're dragging my poor sil out next weekend to play.