This beautiful part of town is in stark contrast with skyscrapers and fashionable stores of modern Tokyo. It is very old and in spite of many tourists it has a unique charm. The temple, also known as Asakusa Kannon Temple as it is dedicated to the goddess of Kannon, is a Buddhist temple that dates back to the VII century.
To get to the temple you first have to enter through the famous Thunder Gate, and then walk through a crowded shopping street called Nakamise that is also several centuries old. There you can buy food and souvenirs, including kimonos and the folding fans. My personal favorite souvenir from Japan is the daruma doll, a little figurine whose white eyes you color with pen - first you color one eye when you make a wish or set a goal, and then the other one when the wish/goal is achieved. I swear it works......
After Asakusa you can go to the beautiful and serene Hamarikyu Gardens by taking a water bus (basically a big boat) and sailing down the Sumida River. The ticket from Asakusa to Hamarikyu is between $5 - $10, and the ride lasts between 35 - 60 minutes, depending on the boat you take. Watching Tokyo from the river is a nice experience, but given the boat can get busy and you may not find a seat, it's not a must.