Attention Puzzlers: Advent of Code 2016
If you are looking for a little extra challenge this month, consider playing Advent of Code. A pair of holiday themed problems are presented daily, December 1-25. I'm not trying to steer people from CheckiO; I'm just sharing another option available for the next three weeks.
I'm not affiliated with this site, and honestly can only answer the first few problems presented! :)
Good luck & have fun!