When this happens to me, I like to strip it back down to basics. I'll literally pull everything off my kit except bass and hats. I'll listen to and play with some tracks and it has to be interesting with just the bass and hats. After a day or two, I allow myself a snare, then a crash, then one tom, then maybe a splash, and so on. Doing this helps me remember WHY all of the things are there. It's easy sometimes to just hit something because it's there or to think that more gear will make you more innovative, and it can, but if you break it down to grass roots, you tend to learn to make different sounds with each item and tap the full potential of each drum/cymbal. If that doesn't work... get more COWBELL.