There are TWO challenges for Expresso bike riders for December.
First there is King of the Mountian.
Each ride has a certain amount of points you can earn based on the difficulty of the elevation. Your goal is to get to 50 points.
You can see the point breakdown here.
The other challenge is a bonus challenge.
It is called the Legend of the Abdominal Snowman
You can choose 25 miles, 75, or 125
Each stage has a set list of rides for you to accomplish. You start in the 25 mile and work your way down.
You do need to register for which stage yo are committing to.
Check out the rules here
As usual if you have questions, ask!