 <p>You can write a Diary application. Whose functionalities include:-</p> <ol> <li><p>Writing the daily diary and saving it which must be searchable via data/keywords(Basic function)</p></li> <li><p>Contacts with basic information about the person.</p></li> <li><p>Give a feature to export your matter to a suitable file format, say doc.</p></li> <li><p>Of course, login with password for different users, you can use file systems to store the data(but in encrypted format).</p></li> </ol> <p>This will be a good application to start with. :)</p>