I'm slightly obsessed with this SunJar from the Museum of Modern Art store; check this out:
Inside this traditional Mason jar hides a highly efficient solar cell, rechargeable battery, and low energy LED lamps. Place the jar in the sunlight and the solar cell creates an electrical current that charges the battery, powering the three LED lamps and providing diffused and warm light from the frosted jar during the night. Completely water tight, the SunJar can be left outside in any weather condition and is the perfect garden light or night-light.
How great would these be for a party or wedding?! I love, love, love this idea.