If you need a break from the rain, check out the Animation Building in DCA, or sit in front of the fire in the "Great Hearth" at the Grand Californian... I love it when the storyteller and the campfire song people come around, it's so cozy there. Try to find the rides with inside queues and shows that are indoors. If the rain is really bad, go see a movie in DTD, have a nice sit-down meal, or take some time away from the parks to go to the Character Warehouse Store. Or, you can embrace it and ride Splash Mountain and/or Grizzly River Run over and over again...