These are my past LudumDare competition entries. Hopefully I'll find the time to do more in the future =)
Ludum Dare 21
August 2011 - Land of Colors I remember coding this on the last two days of my summer break, spontaneously. The theme for the game was "Escape" and we had 48 hours. The entire code is in Java, no libraries used.
Ludum Dare 30
August 2014 - UltraRealistic Moon Wrecking Ball Simulator An entry done in short time to the theme of "Connected Worlds". My second LD48 entry ever, was great fun. Pure Java aswell. This entry lives in its own repository: https://github.com/ZirconCode/LudumDare30
Some resources I've used in past LD's: