I figure this would make a good blog post for new fans of the sport... please contribute any nuggets to the thread and I'll compile them into a blog post
GC = General Classification; The ultimate winner of the Tour de France wins the General Classification and wears the yellow jersey.
TT = Time Trial; all riders complete the same course racing against the clock. The best
Jerseys
Yellow = General Classification; The race leader with the shortest time accumulated on all stages
White = Best young rider; Same as the Yellow but only for riders under 26
White with red polka dots = King of the Mountains; Rider who has claimed the most points in designated climbs
Green = Sprint; Rider who has claimed the most points in designated sprints
Climbs
HC = Hors catégorie; a hill climb that is so tough it is beyond categorisation. Originally used to describe mountain roads where cars were not expected to be able to pass, these climbs include an altitude difference of at least 1,000 meters and have an average grade of at least 7 percent.
Category 1 climbs last 20 kilometers with an average 6 percent grade and ascend 1,500 meters.
Category 2 climbs are 5 kilometers or longer at an 8 percent grade and ascend 500 meters.
Category 3 climbs last approximately 5 kilometers, have an average grade of 5 percent, and ascend 150 meters.
Category 4 climbs are short and easy.
GC = General Classification; The ultimate winner of the Tour de France wins the General Classification and wears the yellow jersey.
TT = Time Trial; all riders complete the same course racing against the clock. The best
Jerseys
Yellow = General Classification; The race leader with the shortest time accumulated on all stages
White = Best young rider; Same as the Yellow but only for riders under 26
White with red polka dots = King of the Mountains; Rider who has claimed the most points in designated climbs
Green = Sprint; Rider who has claimed the most points in designated sprints
Climbs
HC = Hors catégorie; a hill climb that is so tough it is beyond categorisation. Originally used to describe mountain roads where cars were not expected to be able to pass, these climbs include an altitude difference of at least 1,000 meters and have an average grade of at least 7 percent.
Category 1 climbs last 20 kilometers with an average 6 percent grade and ascend 1,500 meters.
Category 2 climbs are 5 kilometers or longer at an 8 percent grade and ascend 500 meters.
Category 3 climbs last approximately 5 kilometers, have an average grade of 5 percent, and ascend 150 meters.
Category 4 climbs are short and easy.