That huge hot air balloon that floats over the Philadelphia Zoo is not just for animal lovers. It turns out that it is a separate activity from the zoo itself, so you can invite out-of-town guests to float over the city with you without going into or paying for zoo admission. The balloon has a separate entrance and costs $12 for about a 20 minute lift up - float on tether - and pull down. All enclosed by mesh, so you can't fall out. Great 360 degree viewing, and a continuous recorded message about what you are seeing in each direction. Zoo parking, however, will set you back about $16 unless you are willing to walk from neighborhood parking about 3 1/2 blocks away.