The non-profit built for "opening America's government" has created an app to show off its Congressional data, as well as its API (our Sunlight Labs API profile). You can't get this app on the web, though, as it's available exclusively for the Android phone platform.
Developers worried about surpassing mobile app size limits can find salvation in the new modular SDK from MoPub. It allows developer to customize the SDK for only the ad formats they want or need to use. This means developers have more control over their app's size and can improve performance.