The Athlete Recovery Fund is a Californian non profit organisation that supports injured pro riders in BMX , MX and skateboarding. However, this video they have produced is relevant to anyone riding a Non-certified helmet and the results are really quite shocking.
The non-certified helmet they test is the ProTec Bucky Lasek Classic helmet which is apparently favoured by skate park riders as its cheap and comfortable. Personally, I’ll keep paying the extra money for a Fully certified helmet.
UPDATE: This is even more amazing considering that this fella can make a cardboard that can be certified!