c:geo - c:geo is simple yet powerful unofficial geocaching client for Android devices.
The Tweet Hereafter - The last tweets of the deceased
GSAK (Geocaching Swiss Army Knife) - GSAK is the all in one Geocaching and waypoint management tool.
Scavenger - An augmented reality scavenger hunt for cash prizes
iCaching - iCaching is the all-in-one Geocache manager for the Mac.
WeCroak - An app to remind you of death