Coworker Coffee - Coffee with a different coworker each week
Focus - New Tab page that gives you a moment of calm and inspires you to be more productive.
Serendipity - Serendipity is a PHP-powered weblog engine which gives the user an easy way to maintain a blog.
Calm - Calm.com can help you reduce stress and increase calm.
Virus Cafe - Make a friend in 2 minutes
Slack Wellness Coach - Short exercises, meditations and water breaks