I am sure some of you are familiar with the concept. You may also know that CFL's are considered one of the worst offenders people are exposed too. I am sure Paul's friend from the podcast about CFL's understands the sensitivity of seizures induced by unwanted frequencies.
The idea is that you are shunting a lot of noise that is otherwise getting into everything that uses electricity around you.
Ideally this would be placed somewhere pre-sitting/sleeping area on the same circuit. However so long as it comes before the items you have plugged in around you, or at the same power strip, it will work.
I sleep better as far as I can tell even though I am not doing a controlled test. My nightstand has a fan, alarm clock, and light on it (all AC ran).
The filter consists of a 25uf capacitor (AC rated), and a 2 million ohm resistor across the switch so it will discharge the capacitor when you turn it off. Without the resistor it would discharge when you remove it, causing an arc (I had a crude version and it arced real easy). I also earth grounded the case for safety.