I didn't join Strava until June, when I got the Garmin, and only signed up for three challenges this year, but here are the badges. I completed the Rapha 100k in July, and earned 250K benchmarks on the other two. (Three on The Extender and one on Turn up the Heat.) Each benchmark met personal goals, so that was great. Next summer, I'm going for a 1,000km month. Definitely.
Rapha Womens 100 -- 7/7/13 Total distance: 100K 1 day
The Extender -- 9/1-9/30 Total distance: 802.5k over 14 rides,
Turn up the Heat -- 10/1-10/31 Total distance: 351k over 4 rides