I need ideas...

XKCD Comic #716
I want to make something cool.....but what?
There is no right way to go about designing the next light bulb, but here are a couple ways to get started. Also, don't let yourself get stuck in the mindset "I can't come up with anything"....you CAN come up with something, and you CAN make it amazing! There will be a workshop on this topic, so if you can't come up with anything right away, don't give up!

One good way to get started
1) Look at things that are familiar to you.  Think about your favorite toys growing up, your hobbies, your daily routine.....basically your everyday world.  Have you ever been doing something and thought to yourself "What if this do that? That would be awesome!" or "If I had something that could do this, my life would be SO much easier!"?

For example, a colorblind man would find it great to have a device that tells him when his clothes don't match.

2) Analyze your idea. Who would be using your gadget?  What types of features would accentuate your device or make it easier to use?  What could features I add or subtract to make it better and easier to use?

Normal vision views an 8
Colorblind view a 3
In the example, colorblind folks would be using this device and would need a user interface that doesn't require color to operate it. Beeps and sounds might be a good way of communicating a match or not and would simplify the interface.

3) How could you make your idea a reality? What parts would you need? Are there people and resources around you that could help you achieve your goal?

In my example, you would need a color sensor (backwards LED's work well), a push button, a microcontroller, and a buzzer for feedback.  You would also need to talk to people to help you create a list of colors and shades that don't work well together.

4) Sell. An invention or product is useless if you don't get it where it is needed.  You should be able to readily demonstrate your invention and how it can make people's lives more enjoyable.

Another (just as) good approach
Look through your bucket of old toys, thrift stores, and garage sales for old electronics toys.  Chances are, you'll find something interesting.

Take it apart (don't destroy it, you may want to reassemble it later) and see how it works.  Look at things like gears, wheels, speakers, buttons, and whatever else is there.  What could you add to control this device easily?  What extra features could you add to this device to make it work even better or do something that it wasn't designed to do? Would these alterations and new abilities be useful or just plain cool? Are there any other devices that you could connect to expand it even further?

For example, you could look at a remote control car.  If you take apart the car, you start seeing things like a gearbox, RF antennas, transistors, belt drives (sometimes), and more.  If you start to think about it, one of those gears could turn a belt made of a piece of string.  That string could be attached to curtains perhaps. Wouldn't it be cool to have curtains that shut when it starts to get dark?  If you interfaced with the Arduino and a simple light sensor, you could make self-closing curtains in no time. The idea for the device is simple, easy to make, and extremely useful (and is also owned by the creator of this page, so it's off limits).

Like the process above, you should be able to explain why it is useful/consumable and be able to demonstrate it easily.