Indoor gardening and composting
Aquaponics
The art of gardening without soil. Makes my geek heart vibrate.
Here is an example of how to create a solution with Ikea stuff. There are both more complex and simpler ways to accomplish this.
Bokashi
Instead of simple composting; first ferment and get some juice out – then compost.
With a bucket under the kitchen sink one can play with the food that wasn’t eaten. Here is a Swedish site for the stuff.