Yellow, White, Green . . . Polka Dot?

I'm going to assume that everyone has at least heard mention of "the yellow jersey." It is one of a number of visual indicators of the different classifications in the Tour de France:

The Yellow Jersey (maillot jaune) - indicates the leader of the general classification (GC); the overall leader of the race.

The White Jersey (maillot blanc) - indicates the highest placed rider on GC who is under the age of 25; the Best Young Rider competition.

The Green Jersey (maillot vert) - indicates the leader of the sprint competition; the points classification.

The Polka Dot Jersey (maillot à pois rouges) - indicates the leader of the climbing competition; the King of the Mountains. It is white with red polka dots.

Even though each team has sponsored jerseys with particular colors, those leading in each of the categories get to wear that jersey instead. If a rider is leading two (or more) categories, the second placed rider gets to wear the less important one.

Additionally, each country holds a race to determine its national champion each year, and each current national champion generally wears his national champion jersey instead of his team one. The world champion gets to wear a white jersey with rainbow stripes. The olympic champion gets to wear a golden helmet. There are probably other special colors, too, just never lose track of that yellow jersey.

The determination of the yellow and white jerseys are pretty straightforward. The green and polka dot ones are a bit more complicated. Each stage finish is worth a certain number of sprint points for the top 20-or-so riders (it varies depending on the flatness of the stage). And tucked within each stage are a few intermediate sprints worth points to the first three riders to cross them. So the wearer of the green jersey has done the best job earning a combination of stage wins and intermediate sprint points. The climbing points work much the same way, except they are awarded at the top of peaks. The harder the climb, the more points. Climbs are categorised from 4 (easiest) to 1 (hardest), with a few climbs rating HC: too hard even to rate on the scale (Hors categorie/outside category). The wearer of the polka dot jersey has earned the most climbing points.

In addition to points, each of the sprint competitions includes time bonuses. Thus we have seen the lead change hands each of the past two days despite everyone finishing in the same time. Thor Hushovd won the time trial prologue, but George Hincapie finished second by less than a second. On the first stage George got a 2 second bonus on one of the intermediate sprints and took over the yellow jersey (becoming only the 4th American ever to wear it) for today's stage. Hushovd, Tom Boonen, and Robbie McEwen (the stage winner), top sprinters all, earned enough bonuses today to jump ahead of Hincapie, and Hushovd will be back in yellow again tomorrow.