Moon. This app calculates the distance to the moon, gives you the current moon phase and will alert you of the new moon and the full moon. If you love the moon, then this app is for you.
Stellarium Choose your location and watch Stellarium light up the stars, the constellations and the planets. Neat. Recommend!
Artfinder Never miss a gallery or museum showing in your neighborhood again. This app is so cool. I've discovered a bunch of galleries in my neighborhood I never knew existed. An excellent and well executed idea!