31 Days of Mango is a series of articles that cover development for Windows Phone 7.5. For each day of November a tutorial about some aspect of Mango development was posted on Jeff Blankenburg's blog. A broad range of topics has been covered including Gyroscope, Raw Camera, Motion, Background Task, File Transfers, App Connect, Execution Model and more.

Taken as a whole the series of tutorials is amazingly detailed and  is a great way to brush up on the changes introduced in the first major revision of the Windows Phone platform.  Generously the contributors are giving away the information for nothing in its web version. However, you can support the authors by buying the 31 Days of Mango app or ebook version of the series (available for Amazon's Kindle and Barnes and Noble's Nook).

The 31 Days of Mango project was instigated by Jeff Blankenburg and various people have contributed to the series including Jared Bienz, Samidip Basu, Jerrel Blankenship, Dave Bost, Michael Collier, Matt Eland, Jeff Fansler, Gary Johnson, Parag Joshi,Chris Koenig, Doug Mair, and Chris Woodruff.

The articles have also been translated into a number of languages: Chinese, German, Russian, and Spanish.