Do you know about the Animator's Sketchclub? As their home page states, it's an "online drawing community for animators of all kinds", with over 6500 members enrolled to date (Nov. 4th 2016). Every month Tony White sets up a challenge for all the members, all who can join in and hope to win. I have yet to win that Pencil and when I do I'll be sure to post it here :)