Lately, there has been some bug found in DotA 6.66b with PitLord's Firestorm which is instantly stopping, if PitLord is getting Bristleback's Viscous Nasal Goo buff on it. It quite abuse-able, not worth gamebreaking but one can use it for it's own advantages. Check it out yourself.
Also, check this funny neutral creeps bug:
If you have found any Dota 6.66b Bugs or any exploit, you can share it with us anytime via comments.