Like a tunnel of love with credibly educational overtones, the Tactile Dome will have you crawling, sliding, and climbing side by side with the object of your affection in complete and total darkness. Go ahead, reach out and grab something. The whole point of this fantastic 1971 exhibit is to reacquaint visitors with the remarkable and too often neglected sensation of touch. As you clamber through the maze, housed within a geodesic dome (or Bucky Ball, as we like to call them), your body is exposed to a profusion of textures and sensations -- from the cool, jagged edges of a set of house keys to a warm, plush pelt of fur. Should you accidentally graze that special someone's knee as you giggle your way through the labyrinth, all the better -- the Exploratorium's motto, after all, is "Please touch." One caveat: Be sure to make reservations a week or so in advance; spaces are limited to keep the experience -- ahem -- private.