WWDC 2011: The Musical, handheld games, Dos and Don’ts, Mozilla Demos, CSS quiz

This week's assortment:

- A gallery of retro handheld games collection.

- How well do you know CSS? Take this quiz to find out.

- 10 useful .htaccess snippets to have in your toolbox.

- A list of Dos and Don'ts for creating iPad apps.

- An infographic on the who, why, and how of Twitter.

- Polycode is an open-source, cross-platform framework for creative code.

- New to PHP? Learn how inheritance works in PHP.

- Did you miss the Apple 2011 WWDC Keynote? You can watch the "WWDC 2011: The Musical" to get caught up on the highlights.

- Use HTML Email Boilerplate to avoid rendering problems with the common email clients.

- Mozilla Demo Studio, where developers go to develop, share, demonstrate, and learn all about Web technologies.