A 24hour relay event at Carron Valley, in aid of Strathcarron Hospice.  From the event organisers:

Stirling Cycle Hub and a team of volunteers are going to complete a 24 hour mountain bike marathon relay between 12 noon on Saturday 19th September and 12 noon on Sunday 20th September in aid of Strathcarron Hospice.  We are setting ourself the target of 100 laps in 24 hours and would really appreciate your support.  Please check out our website for further details 

http://www.stirlingcyclehub.org/

Event details:

http://www.stirlingcyclehub.org/news/186-calling-all-mountain-bikers