Use your engineering know-how to help others with different needs. This great list of resources is full of ideas for how you can participate in projects that improve lives.
Another great resource for all kinds of things you can build for an active lifestyle. These are broken down into categories such as hunting, fishing, and gardening. Each example has an article and an image or two of what was built to help out. This resource is so fantastic because it isn't primarily electronics focused. There aren't as many resources for an active lifestyle out there, so this is quite refreshing.
Assistive Technology Solutions
A decent collection of projects in various categories. These can be filtered by what they pertain to, cost, time needed, as well as skill level. Each one has a parts list and a downloadable PDF to describe how to build it. I would love to see this collection expanded.
While most other sites in this list focus primarily on hardware, Game Accessibility branches out a little bit more. There are hardware projects, but there are also plenty of software projects to reference when dealing with something that isn't just a matter of motor control or missing digits. Cognitive needs as well as audio-focused games are addressed here.