The GoGlow Harry Potter light is quite nice, but it only turns off automatically after 10mins. There's no way to turn if off manually.
This light has a momentary switch on the bottom to detect when the light is being picked up. When the light is on the table, an LED inside the owl will light. When picked up, an LED on the bottom will light.

The upgrade repurposes that switch. Pushing it two times within a second will turn the light off. The other functionality remains, although the timeout has been reduced from 10mins to 3mins.

This project describes how to upgrade the light. The original MCU is replaced by an ATtiny402. An extra pull-up resistor and a patch wire complete the modification.