Places I usually visit:

• Dangerous Prototypes: Open Source Hardware Projects.
• Adafruit: Unique & fun DIY electronics and kits.
• Sparkfun Electronics: Online retail store that sells the bits and pieces to make your electronics projects posible.
• Hackaday: Fresh hacks every day.
• Instructables: How to make anything.
• Embedded Lab: Embedded Systems tutorials, projects, and more …
• Electronics-Lab: Electronics Projects and Circuits.
• EEWeb: Electrical Engineering Community for hardware designers.
• All About Circuits: Web-Based community of electrical engineers and designers seeking ideas, education, and discussions.
• Maker Pro: Your Electronics Projects, From Concept to Creation. Design, Collaborate, and Share for Free.

Projects where I join in:

• Leonardo101: Programar es divertido
• Insolito: Control your mobile apps with your Insole

This post is also available in: Spanish