Marble To Go(Navigation Mode) for KDE by Siddharth Srivastava
Add Bookmarking and Annotation in marble for KDE by Gaurav Gupta
Reverse Geocoding and Improved Map Search for KDE by Gabriel Voicu - this project is actually for digikam. There is a wiki page with more information.
Implementing Time Support to Marble for KDE by Harshit Jain