I want to make this: Tron El Wire Bag and I can buy a kit for $20, or the indiviual components for a bit less.
And then I read on the Make Blog that someone has done every single experiment in their electronics book: Make Electronics. I got this book for my birthday off my Amazon wishlist and have gone through it but haven't done anything yet. I still have a decent breadboard and some leds, resistors, capacitors, etc so I have the stuff, minus the El Wire. I have to do this, every single experiment in the book, I can do it but it will probably take more than a year.
When I took my first Physics lab class and we got into this stuff I immediately went home and took apart my hairdryer and toaster and headphones and so much other stuff to scavenge for parts. It's probably good I don't do that any more.