Back in March there was quite a bit of hype around a system called App Inventor. It was an online tool for creating mobile apps (android), originally developed by Google and later provided by MIT. You can never tell how long these things will last, but it is still available, and still free. If you want to create your own apps, then this is probably the quickest and easiest way.
Continue reading for an overview of how the system works. Note, you will need a Google ID in order to use the system – for example from GMail or Google+.