The Game Maker's Toolkit jam is one of the biggest game jams out there.
The creator Demeno has created a fiendishly difficult puzzle game, Pixcale, for this year's GMTK jam! It can be bit difficult to get started (hint: try clicking inside the squares on the left to build up squares on the right). Once you get the hang of it, it becomes a very fun challenge!
The voting is still going on at time of writing but we wish you a lot of success Demeno!