In 2013 and 2014, I spent this week in Chamonix soaking up international trail running culture (along with a little Bordeaux) and preparing to run UTMB - well, most of it anyway. No regrets and I'm still finding it fun to watch the live coverage website this week. There are 6 events now, the first of which (PTL) started on Monday and is still going on. What an amazing adventure it was, DNFs and all.
http://ultratrailmb.com/en/