By participating in a few hackathons that last only 2 or 3 days as an Android mobile developer, I realized that most of the time you should better just explain your application idea as a prototype than actually coding it. Coding an app alone for a week-end can lead to good results but I believe that you can do much more by just focusing on user experience and design to show your idea. In a first hand I really love to code but doing some unreadable code in a week-end is not as good as showing just what could be the actually developed application.
This solutions are good for developers, designers and any other users as you don’t need to code.
Hera are a listing of few tools that are really good for prototyping mobile apps (Android and I-Phone), just click on the image to get to the website:
Marvelapp.com is my second choice to create prototypes. It’s simplicity and great compatibility with psd make it a good choice if you have to create an app prototype quickly.
Invisionapp.com is also a really good choice to create your mobile app prototypes. I really enjoy the collaborative features that it offers.