When you're at an outdoor concert or are having your home bathroom remodeled, those rental porta potties can be your best friend. Many places where building a bathroom with standard plumbing is impossible or impractical are made accessible and comfortable by bringing in porta potties. Also known as porta johns, tidy johns and port-o-lets, you can find them everywhere from the presidential inauguration to the Grand Canyon. In fact, the largest ever gathering of these facilities was at Barak Obama's inauguration in 2009, with a whopping 5,000 porta potties on hand. So, how did it all begin?