KAlarm lets you schedule personal messages to display, audio files to play, commands to execute, or emails to send. Among its options, it allows you to choose the message font and color, recurrence schedule, whether to display an advance reminder, whether to speak the message or play a sound when it is displayed, and whether to cancel the alarm if it can't be triggered on time (e.g. if you are logged out at the time). As well as using the graphical interface to configure alarms, you can use the command line, and there is a D-Bus/DCOP interface for other applications.
MuseScore lets you notate and compose music easily with your keyboard, your mouse, or a MIDI keyboard. You can print beautifully engraved sheet music or export it as PDF or PNG. You can play your score, transpose it, and save it as audio or MIDI file. MuseScore also supports MusicXML to let you share your composition with other scorewriters. MuseScore is often advertised as a cost effective alternative for Sibelius and Finale.
ReplicaNet is an object oriented C++ library for developers of applications that require a stable and low maintenance middleware solution to networking. Any project that is designed to use a network of machines, such as multiplayer computer games, need to very carefully consider how to approach the design problems associated with networking. It includes support for binary difference patch creation and delivery, backend availability and TitleID verification, Internet CD/license key verification, NAT detection, advertising and querying of sessions, user accounts, friends lists, game invites, chat rooms, persistent data storage, and statistics and ranking.