JLearnIt is a thematic dictionary that allows you to learn vocabulary with a questionnaire. You can also translate text (word by word), search for incomplete words, sort the languages in alphabetical order, rearrange the order of the languages, save your score, save as HTML, and show only the languages you're interested in. Each word is rated according to frequency of use. You can choose to see only the words of a certain range of frequencies or to be asked for words of that level. You can also add and delete your vocabulary and categories, and cut/copy/paste between a spreadsheet program and JLearnIt. You can change the language and the skin of JLearnIt. You can get more information about the word on the Internet and save your configuration. JLearnIt won't ask you the same word if you know the word. It won't ask you for the word that starts with the same letters as the translation. You can edit words and set properties for this word.
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.
KeePass is a light-weight and easy-to-use password manager that removes the need for you to remember many different passwords and makes it more feasible to use different passwords for each account. It manages your passwords in a secure database encrypted with AES and Twofish, which is locked with one master key or a key file.
Kronolith is the Horde calendar application. It provides a stable and featureful individual calendar system with integrated collaboration and scheduling features. It makes extensive use of the Horde Framework to provide integration with other applications. It implements a solid, stand-alone calendar system, allowing repeating events, all-day events, custom fields, keywords, shared calendars, iCalendar support, generation of free/busy information, and managing multiple users through Horde Authentication.