With the Ski cross race at Nationals this year, the Chelsea  Sprints will be set up as a training event for those going to nationals. There will be an escargot and a step over as the nationals organizers have suggested. There will be many other obstacles and challenges in the course.
The course will be 600-750m long and the event will be run Kings Court style. It is going to be a fun event and here is the registration info: