Get to a Maker Faire. Several years ago I spent awhile talking with Bre Pettis about his new machine from MakerBot without realizing who he was. Take the kids! Solder your own badge! Learn how to make your own air powered rockets! My kids aren't even into robots think it is a blast. A word of waring... they make you sign a serious waiver for a reason. They expect you to pay attention to your surroundings and not blindly walk into that quadcopter demo. Make sure your kids are not texting as they walk. Look for some of the small booths/tables with guys that brought in their home brewed stuff. They were you not that long ago and would love to talk about hot to get started. The fancy booths are people looking to sell stuff. If your not looking to buy your own laser cutter.... they will let you look and they will be polite but they are looking to sell stuff.
If you decide you want to start now and want to learn how things work....
Get this kit for $49:
Follow the tutorials starting here:
Soon you will be a master of blinky lights. Think of it as "Hello world" for robotics.
If you think, "HOLY CRAP. I AM MAKING IT REALLY DO THINGS" Then continue. If you went, "HOLY CRAP, I JUST WASTED $50 AND A FEW HOURS OF MY LIFE TO MAKE A STUPID LIGHT BLINK" you might consider some of the more expensive options or re-consider your desire to do this. If you want to continue...
If you have an old printer laying around then rip some motors out of it. In fact anything that has a motor or is older electronics will soon be looked at with, "Hey, that has a nice transformer in it. Those are some nice through hole resisters. Would you look at those hardened steel rods! I wonder why they did it this way?"
Things to consider furthering the addiction:
motor shield with some basic motors
Soldering iron, do not get one of those nasty Radio Shack $20 pieces of junk. You wouldn't try to build a small deck with a handsaw. This is one of the more expensive pieces you will buy, but it is one of those tools that you will use and will appreciate not having a junk one. This does not mean you need to get a super solder re-work station. Get one with a base station and dial control. Temp controlled would be great.
Go to a nearby electronics place that sells this stuff and buy some general wire, breadboard etc. They will appreciate the business and might be there someday when you really need that one part and don't want to wait for shipping. I was amazed to find one near me. They were rather knowledgeable compared to some certain chains (they had a soldering iron on the counter just in case)
An old computer with the following ports: MIDI(computers used to have a port with real IO, oh my), serial, USB, parallel. You might want to eventually talk to ports and individual pins without the OS in the way. Windows stopped allowing this with XP. A P4 is fast but gets warm and very power hungry. A PIII not so hot or power hungry but not as fast. An old laptop works great for this since it has a small footprint.
Start to follow a few web sites: