Karneval is a 5 day affair in this part of Deutschland, all along the river Rein, even including some Holland cities. It begins on the Thursday before Ash Wednesday. They call this day, "Fett Donnerstag," or, "Fat Thursday." It's called that because there's some kind of traditional fatty cake that's supposed to be made on this day. I have not seen one. The next three days aren't that important in Germany. I think that they give them each a flower name like, "Nelken Freitag," "Tulipen Samstag," and "Lola Sonntag," (the last I believe I made up) but they aren't really official. Monday is Rosen Montag and it's the day for the biggest parade. I totally forget the name for today, Tuesday, but it's got something special that's not entirely related to partying. (I'll edit it in later.)
Also, they have a day for the women (Thursday) and a day for the children (Monday). On Thursday at 11:11AM the women (in Aachen, at least) get the keys to the Rathaus (townhall) and open it and take over... or something like that. There's a whole bunch of dancing and music on this day; lots of kids about my age getting sloshed in the streets. Monday is the big parade day and they throw out TONS of candy in the streets.
They also have these... I'm not sure what to call them... royal families of Karneval, perhaps. A committee selects a prince, a treasurer, and some other folks and they become in charge of the communittee for the entirety of the festival. Kelmis, where I live, places a lot of importance on this and I would imagine that other small towns to as well. The prince has to attend all sorts of local events; I'm thinking stuff like BINGO at the old folks' home, but I'm not really sure.
Here's a photo of a friend of mine who was the treasurer in Kelmis a year or two ago:
The costumes varry a good bit. This one here is very traditional and very expensive. Like, €1000 or something. Some costumes are very ridiculous-looking; glittery, puffy sleeves and the like. Most are just very nice suits with the traditional hats like you can see in this picture:
There's a special kind of Karneval dance as well that can be pretty bad-ass. Because I cannot explain it very well, I'm posting the first two adequate YouTube videos that I found. The first is of some younger girls; you can see in the back the Karneval prince and the other important people. (They're wearing nice suits and funny hats.) The second is older, more skilled women dancing. Neither video is the coolest that I've seen, though. If they've got guys up there with them, there's be lots of lifting, throwing and tossing. Sort-of like "Bring It On," but German-style.