Appcelerator Titanium - Appcelerator Open Source
MagLoft - Mobile app publishing and digital publishing solution. Create your own native mobile apps for your digital magazine, blogs and more. Start publishing today!
B4X - Cross platform development tools for native iOS, Android, desktop and server applications.
RhoMobile - RhoMobile is a based on the Rhodes open-sources framework that has a massive range of advanced development tools for creating data-centric, native mobile consumer, cross-platform and enterprise application.
Apache Cordova - Platform for building native mobile applications using HTML, CSS and JavaScript
Sencha Touch - The leading mobile web app framework based on HTML5 for amazing mobile apps.