This is not so much a local custom, but rather a local food! Ahle Wurscht is as typical for Kassel as the gingerbread is for Nuremberg or the Grüne Sauce for Frankfurt. Ahle Wurscht can be translated with "old sausage", but this should not terrify you. This special kind of sausage tastes best after at least a week. If you get the chance, try it! Many of the local pubs offer Ahle Wurscht as "good with beer". If you want to buy it yourself, go to any butcher in the city - they all have it. Ask for a "Dürre Runde" if you prefer a longer but bent one, or for a "Stracke" if you prefer the long straight one.
Finally, here's my secret tip: The very best, the ultimate Ahle Wurscht can be purchased in a village near Kassel called Ihringshausen. Search for "Fleischerei Lämmerhirt", a butcher just next to the station.
There are so many things to do in Kassel. It's a place which literally reeks culture. The best way to learn more about Kassel itself and it's phenomenal structures is to stroll through the town, visit the monuments and go to a few museums. I'd be here a couple of days if I would list everything.
You might want to try to go to Kassel.de on the web. I can't guarantee if it is in English. But they have some addresses and phone numbers listed which might interest you if you're ever in the neighborhood. It's very worthwhile going!
The DOCUMENTA, exhibition of modern art, is held every 5 years in Kassel. So again this year, 2002.
For more info take a look at DOCUMENTA.
I didn´t visit the Documenta this year. I only spend a few hours in town and decided to visit Parc Wilhelmshöhe and to make a walk up to the Hercules momument.
In 2002 Kassel becomes the world capital of modern art. Every five years, since the early fifties, the 'dokumenta' takes place in Kassel.
Far from being provincial, for the summer period Kassel gets a cosmopolitan touch, hosting art lovers from all over the world.
For us it'll be our third documenta; best was the one of 1992, merely unique in atmosphere.