Cuteathon
The second annual cuteathon will take place during the so-called Hackathon at Wikimania. Organized by participants of the #wikimedia-kawaii channel, this event will spread happiness among participants. Participating requires very little knowledge ahead of time. If you're feeling stressed and want to yell at PHP/node/Objective-C/etc., this is the perfect place to unwind.
To participate, simply join #wikimedia-kawaii on IRC and post links to your favorite cute photos.