Alchemy OS is a MIDlet which creates an operating environment inside a mobile phone. Although it is not an operating system in the full sense, it provides a rich platform to develop, compile, and run applications directly in the phone.
CrazyGolf is a Java-based crazy golf game (also called "mini golf") for mobile devices with a touch screen supporting CLDC-1.1 and MIDP 2.0 with an HVGA screen resolution (320x480). The game also comes with an editor that allows you to design your own golf courses on your PC.
PrefixDB is a mobile database of callsign prefixes in use by amateur radio. This database is helpful for the radio amateur while on the run. It is especially helpful for portable operations like QRP or handhelds (Echolink, etc.).