What: I will solve any technical problem you have and give it to you for free (within reason, for example, if it requires any purchase on my behalf I would expect to at least recoup it, but I will not ask anything for my development time). It can be anything, hardware, software, service, etc…
Why: I want to increase my Computer Science / Electronics skill-set by doing things that matter instead of just “toy projects”. I want to solve an actual pain for someone.
How: Post a problem you face and elaborate a bit - I will try to better understand the cause of it. Users that also have the same problem please upvote so that I can see it's not a single-man case (see the "why"). I will chose one to work on based on the popularity and my ability to deliver on it.
When: I will work part-time during workdays and full-time one day over the weekend to deliver a solution.
You should work on an open source project.
There are plenty of large projects that would be thrilled to have a developer who wants to tackle something more than a small bug, but you have to go find them.
Moreover, open source projects are much more deserving of your talent than the people posting on this thread trying to get some free work out of you. Don't undervalue yourself.
What are you interested in?
Personally, I have contributed to Python, Django and AngularJS because I use all three on a daily basis. Think of something that interests you and I'd be happy to help you find a project that fits your goals.