The PSXSDK is a free and open source software development kit that enables anyone with C programming knowledge to make programs and games for Sony's PlayStation console. Everything was either written from scratch or based on already available open source resources. It is thus free from any proprietary code and fully legal to use. The SDK is mostly geared towards a *nix environment, but is fully usable with emulation environments such as MSYS and Cygwin.
Android Studio is an IDE and SDK for Android developement built on IntelliJ IDEA. It provides various build schemes and APK packaging + signing, rich and context-sensitive editing and refactoring support, GitHub integration, mobile device emulations for debugging, Gradle support, a flexible and multi-screen UI, Google Services and Cloud integration templates, and runs on all major platforms.