I honestly do not recall the exact name of the waterfalls in Portuguese, but it translates to the "slippery falls". The reason is that there is one massive rock, angled ~45degrees with a gentle flow of water. Couple that smooth rock, with the water and a little bit of the natural moss, the rock makes for a perfect water slide (see first photo).
The waterfalls are less of a falls, but more of a series of pools. The water is fresh and cool, which complements the hot sun. There are a set of maybe 3 pools, all large enough to let you relax and refresh.
This is about 10km out of Paraty. Follow my other tip's instructions for how to get to Penha.
Equipment: Bring towel, insect repellent, sun cream and what ever food/drink you like. Also smart walking shoes would be recommended.
In Paraty, you can go trecking across the "Golden Path", the one used by the slaves to bring the gold from far Minas Gerais province to the port of Paraty. You can do water sports at the beach, play beach volleyball, surf... well, there are a lot of sportive things to do.
In my oppinion, however, the most exciting is diving. There are some beautiful tropical fishes in the Bay of Paraty (not so beautiful as indic-pacific species, but beautiful anyway), and they teach you how to dive, in "courses" that you can arrange next to the pier.
Equipment: The societies that teach how to dive, and the ships that lead to these programs, have the necessary equipment. Sometimes, the price of the tour doesn't include a part of the equipment, so you should talk first about things included in the price.
Again, this was an amazing way to experience eco tourism in Parati. Beware - some of the trails you walk on will be wet and slippery and you will be crossing some flimsy bridges. Watch out for fire ants and mosquitos. Make sure you go with guides who are familiar with the terrain.
Equipment: Eco Paraty provides a lot of tours for hiking or swimming.
We joined a hiking tour to see some cachoeiras (waterfalls) in Parati. I would highly recommend doing this when in Parati, however be prepared for a seriously strenuous activity. The tour took almost 8 hours and we visited several waterfalls and tasted cachaca at rustic distilleries along the way. This was grueling exercise in the heat and humidity, but well worth it!
Equipment: Must have comfortable, closed shoes for hiking. Do not wear hiking sandals - someone on our tour was bitten by giant red ants on his foot!