Develop skills in OO analysis and design, using .NET platform.
Simple personal contact database. 3 entities - person, contact and contact type.
Keep track of your contacts, filtering/searching. Statistics about contacts - how many of certain type, persons with most contacts, etc.
Ability to import and export contacts (from json/csv file). Merging of contacts. Deleting - cascade, safe, full reset, etc.
Use console app. No persistance - everything is kept in memory. Input validation and sanitization.
Console.WriteLine(), etc. for basic UI. Use colors.