Really digging Duolingo's official 100XP challenge on the Android app. :D
Check out what I discovered today:
Click for larger image
I'm not sure if the challenge an A/B or not. I checked to see if there were any announcements and I didn't see any. The only mention I think I've seen was someone commenting in the September bunny XP challenge. Though, I'm not certain.
Anyhow, so far I'm really digging (liking) it. Even though I'm already doing the bunny challenge, Duolingo's new official challenge makes me want to complete it immediately. If it is an A/B test, I hope it succeeds and sticks around. :)