Actual Number Picker is an Android custom-built View for choosing numbers. It's simple, elegant, fits in a small-height constraint box and it can be completely customized in XML. You can easily swipe it right and left, or click on arrow controls to increase/decrease the current value.
Foursquare like map demo with using modified AndroidSlidingUpPanel.
Disk LRU (least recently used) cache with persisted journal. This cache has specific capacity and location. Rarely requested files are evicted by actively used. Lightweight and extremely easy to use.