Chances are, at some point in your photography career (or hobby), you're going to feel like you're bored, depressed at your output, bored with what you're shooting or just flat lining. Don't worry, it happens nearly to everyone, and there are a few suggestions to help lift yourself up by your bootstraps.
1. Take a break. Really, put down your camera for a week (or however long you need) and rest. Go to the museum, go to the park, go to the coffee shop and write to your journal (see #5 below). Go camping for a few days. Without your camera, just use your eyes.
2. Bribe yourself. Sometimes what you need more than a pep talk is a little gift to get your creative juices flowing. Maybe a new Lensbaby Muse or Zipshot tripod will get you shooting, or maybe a nice little point & shoot camera so you don't have to lug your DSLR around everywhere. I have a Canon s90 and a Panasonic GF1 for just those occasions, both of which I like better than the Canon G10, here's a random shot from it:
3. Sit and smoke a cigar for an hour
4. Have lunch with another photographer (or two). Bring your portfolio, have them bring theirs and do a mutual portfolio review. Share some war stores.
5. Buy yourself a copy of The Artist's Way by Julia Cameron (avail in paperback). Honestly this is one of the best things you can do for yourself if you are in a creative slump. It saved me and steered me unerringly in the right direction. Best of all, its easy, all you need is the book, a pen and a pad of paper.