Tokyo used to have a comprehensive network of public trams - 41 lines at its peak - but with the coming of motorization, all but one were discontinued. The Toden Arakawa Line connects the Waseda station with Minowabashi Station, as it runs through the northern outskirts of Tokyo. The tram is away from any major tourist attractions, so visitors probably won't have much demand to use them, but if you want to enjoy the city at a leisurely pace, the trams will prove to be a nice alternative to subways. Recently the Tokyo Governor announced a new nickname - "Tokyo Sakura Tram" - and it seems the government has intentions to make this line more appealing to international visitors.
A single ride is 170 yen and you pay as you get on, from the front of the tram. Suica/Pasmo smartcards can be used and there are announcements and signage in English.
Some points of interest as as follows:
Waseda Terminal, nice neighborhood with the Waseda University and some old Japanese Gardens nearby. However it is not connencted with the Waseda Station on the Metro Tozai Line, in fact it is nearly 10 minutes away.
Zoushigaya Station is adjacent to the Metro Fukutoshin Line station by the same name, providing direct connections to Shibuya or Ikebukuro.
Koshinzuka Station is close to the Sugamo shopping area, aka "Harajuku for seniors". The street provides many health-related items including red underwear which supposedly brings in a good fortune.
Oji Station is the biggest stop along the line, providing transfers to the JR Keihin Tohoku Line (northbound to Saitama or southbound to Ueno, Tokyo and Yokohama) and the Metro Nanboku Line (Southbound to Korakuen and Yotsuya). The Asukayama Park to the immediate south of the station has always been a popular area for the cherry blossom viewing.
Arakawa Yuuen Station is next to an amusement park operated by the local Arakawa Government. The park is open from 9-5 and closed on Tuesdays. Admission is a fairly reasonable 200 yen. The facility lacks an English website (actually there is a complete lack of any info in English!) but some photos can be found here:
Minowabashi Terminal is the eastern terminus of the line, taking roughly an hour from Waseda. (The distance is only 12.2km or 7.5 miles, so that tells you how slow the trams run!) It's next to the Minowabashi Station on the Metro Hibiya Line going to Ueno, Akihabara and Roppongi. It's also walking distance to the Minamisenju Station on the JR Joban Line, taking roughly 15 minutes.