Over the last 2 years we have created some great projects and tutorials for the Raspberry Pi GPIO. These are great for hobbyists, and for students. Here are some highlights.
Electronic Dice project including soldering and Python coding
Using the Mains Switch Widget to switch 4 mains powered appliances
Weighing scales using the Custard Pi 3
Sending an e-mail from the Raspberry Pi
Switching an appliance ON and OFF with an e-mail
Autostarting a Python program when a Raspberry Pi is powered up
If you have any request for new projects, please submit them and we will produce a post on this for everyone's benefit. In fact most of the projects and tutorials above started with requests from hobbyists.