During Christmas holidays I've decided to dive into
Symfony. If you don't know anything about it - it's very nice modular web development framework. Not so long ago Drupal got some low level components from Symfony:
http://symfony.com/blog/symfony2-meets-drupal-8. It was a very interesting merge of the two systems. I was a bit surprised, like when your little sister puts her Barbie into your Ferrari toy car. But as expected it's a well thought though decision: easier maintenance, benefits of small domain components (such as http kernel) and a versatile management system (Drupal, ofc.), merging communities, etc.