La Marmotte (along with l'Etape du Tour) are probably the most famous and two of the most challenging Cyclosportives in France.
Saturday's course:
174 kilometres and +5,000 metres of ascent (+17,000 feet). Three epic, beautiful, and legendary climbs with the easiest being Alpe d'Huez (seriously).
Read the complete post at http://www.cycling-challenge.com/la-marmotte-2008-preview/