Raspberry Pi cayenne is a fantastic way to quickly build IoT applications. Once you have a circuit setup it's as simple as drag and dropping the bits you need.
Picture of Making ApplePi, merging a vintage Macintosh Plus with the Raspberry Pi
raspberry pi car computer - Google Search
Paper piano with arduino - YouTube (Scheduled via TrafficWonker.com)
Raspberry Pi and Arduino serial communication http://www.instructables.com/id/Raspberry-Pi-Arduino-Serial-Communication
These 10 Raspberry Pi projects for beginners are great for getting an introduction to the hardware and software capabilities of the Pi, and will help you get up and running in no time!
How to Solder / Soldering Basics Tutorial - YouTube
Driving CDROM Stepper Motor with Arduino