With Motion Hunter 1.0 you can have your own security and vigilance system to assure yourself that no-one enters your office or room.
It is an application for your webcam which activates a type of movement sensor, so if at any time your webcam detects movement within its field of view, it will set off an alarm (with various alarms to configure), so no-one can enter that space without being detected.
You can configure up to 4 webcams.