The standard tour for newly assigned people was Alte Sachsenhausen, which is a pedestrian zone consisting of cobblestone streets and a variety of bars. My favorite was Spritzhaus, which literally translates to Spray house and the motif is that of a house that stores firehoses. Used to enjoy the live music there immensely, as well as a Bitburger Pils vom fass. (draft) After several little biers, it was off to the main train station and Muenchener Strasse. If you head toward the North east corner, there is an escalator that will take you right up to the street. Walk about a block or so and you'll find Maier Gustl's Bayerisch Bierhouse. As you enter, there is a coat check on your right and a casual bar on your left. If you walk in further, there is a set of stairs leading to a balcony that surrounds the main part of the club. Every table has a numbered lamp and a telephone on it, with which a person can call other tables. A rather fun way to meet people, practice speaking German and just have a good time. Biers come in two sizes, the large being a full liter!!
Fondest memory: Driving on the Autobahn and convenient transportation to and from the city via the train. Great place to party. My fondest memory is dancing until the wee hours of the morning at the Bierhaus, eating at a nearby Vietnamese restaurant and pouring myself and my date into the compartment on the train home. If it hadn't been for an efficient conductor opening our compartment to check for our tickets, we might have had an extra special trip on the S-Bahn that morning!
Favorite thing: Sachsenhausen is a very beautiful area, with its pastel pink, yellow and blue houses. It is mostly a residential area, but there are also a lot of great restaurants and bars. Definitely worth to take a walk.
Frankfurt has a lot of neighbourhoods, that all have names, because they all used to be little towns of their own, that grew together over the centuries. One of these areas is called "Sachsenhausen", a "ghetto" originally built by Charlemange to house the Saxon slaves, hence the name "Saxon Housing". There are two areas here that offer night life - Alt Sachsenhausen, which is a collection of small old houses that over a great international variety of night life, bars, pubs and discos; and the rest of Sachsenhausen - the locals prefer an area around the "Lokalbahnhof" and "Schweizer Strasse".
Fondest memory: For first timers visiting Frankfurt, Alt Sachsenhausen is an experience, especially for those staying in the Youth Hostel, which is located right on the edge of Alt Sachsenhausen. Nothing can replace the first pub crawl in your life, and this is a great place to stage it.
For the more experienced traveler, I would recommend the area around the "Lokal- / Sued-Bahnhof" because the quality and service is much better. Besides, that slight irritation of one pub trying to outdo their neighbours by playing the music even louder is definitely missing here - conversation with your table neighbours is possible.
Favorite thing: See Alt Sachsenhausen. This old part of town is particularly charming and is full of great restaurants, bars, and cafes. The area is probably the best place in the city to sample its specialty, apple wine. When I was there, on a Saturday in June, the area seemed full of people -- most seem to congregate on or around Schweizer Platz (see photo).
i live in Sachsenhausen, the southern part of frankfurt across the river main. I think it's a beautiful place to live, my ex flatmate thinks it's the most northern part of bavaria. (for her that's negative so she visits me only if i threaten her ;-)
sachsenhausen is actually divided in two parts: on the one hand the sort of bourgeios part with houses from the beginning of the 19th century, well restored, lots of trees and a quiet neighbourhood. strange thing here is, you don't see many foreigners. very germanish neighbourhood, but still nice to live.
the other part is Alt-sachsenhausen. i'll put it under warnings and dangers later.
the inhabitants of frankfurt are not known for their friendliness. you can easily spend an evening in a bar without getting to know anybody. can't be helped, just too many people here that are in frankfurt for 1-2 years to work (mostly) in a bank, earn (and spend) a lot of money and then leave again.
frankfurt itself is rather small. you can get everywhere easily and quickly by foot, bike, public transport. i enjoy the most walking around and look at the buildings and the architecture. the westend (located in the ...west of frankfurt) is perfect for this: you can see a lot of impressive Gründerzeitbauten (begining of the 19th century) and the synagogue (easily reconizable by police cars in front). btw, the westend is one the most expensive places to live in frankfurt.