For the basics, I have had a lot of fun playing with the online circuit simulator at everycircuit.com.
I just received an email from them yesterday that they have an Android game Circuit Jam for electronics puzzles. I haven't tried it so I can't yet comment on how good it is, but I intend to check it out with my kids.
I don't know about classes with instructors or discussion groups or the such, but I've personally learned a lot through All About Circuits (http://www.allaboutcircuits.com/).
I agree that Mims' books are easy to understand, but for me they are boring and painfully behind the current state of the art. Horowitz and Hill's Art of Electronics (the third edition is out) on the other hand is readable and holds your interest, and gives you an up to date forest for the trees perspective (it is even funny in places). I also feel obligated to point out Mims' controversies http://en.wikipedia.org/wiki/Forrest_Mims#Controversyhttp://en.wikipedia.org/wiki/Eric_Pianka#Texas_Academy_of_Sc...
Getting Started in Electronics is good, though I think there might even be a more basic one depending on how much you already know. I think they give a good overview with fun projects and get you to the point where you can find more advanced materials on your own and even come up with your own projects.
All About Circuits (www.allaboutcircuits.com) is an expanded version of this open-source textbook.
It looks like any corrections and additions made on All About Circuits feed back to this source too, but AAC has a slightly more web-like layout and links to additional materials (forums, worksheets, video lessons, etc.).
