I had a keen interest in electricity in kindergarden. The bell and buzzer circuits that were common in "science fair" stuff in 6th grade were the subject on my "show and tell" in kindergarden. Both electricity and electronics are great "rainy day" things to do inside. You can get the basic parts at Radio Shack.
You obviously have a computer in the house. The computer merit badge is a good indoor activity too. The weather merit badge is a quick one too.
Look over the requirements here. Quicker and cheaper than chasing down a printed copy.
Anyway Electronics is on mom's want list, but so far he has not really gone for it. It actually looks like a fairly demanding MB to me...
Here is what he has now (non-Eagle) -
He is going to be working on Wilderness Survival next...did you know there is a movement to have it added as a required Eagle badge?
Look at all that "free education" from a lot of professionals. How can any club or other activity come close by comparison in terms of what they have to offer?