The Re-Juicer--Cool Idea!
If you're short a proper citrus juicer but have a large water bottle handy, you can use the bottom of the water bottle as a simple juicer. Larger water bottles have a more pronounced punt—the cone shaped dimple in the bottom of bottles—which can easily serve double duty as an impromptu juicer.
I found this on LifeHacker. [via Coolest Gadgets]