Couple of rules from second game at Dark Star.
Turbo-Penetrator 5th ed Grey Knights Codex pg 53
A Turbo-penetrator shot inflicts 2 wounds on any non-vehicle model wounded, rather than 1.
Context: Vindicare Assassin targeted Justicar with Turbo-Penetrator (I blink in disbelief as I type this. I chose to do that, should've gone with Hellfire round [Ok, new rule regarding drinking at GT's]). Opponent believed that you roll two dice to wound not that one dice counts as 2 wounds. Consulted several other players after the game. They all said opposite, which I agree with. One die roll causes 2 wounds. Not two dice rolls each 1 wound. No GW FAQ for this rule. Jury's still out.
Obscured Vehicles 40k6 pg 75
Picture 3: The entirety of the front of the Space Marine Rhino is hidden by the ruins. However, part of the side of the Rhino is still visible. The Rhino is obscured, and gains +1 to its cover save, for a 3+ cover save.
Context: During the third game a Rhinos front was covered but the enemy could see the side so the Rhino received a 3+ cover save.
Note: Everytime I refer to this rule and show the opponent this page I hear exclamations. These remarks are because people haven't read, aren't familiar with or don't know about this page at all. Rather surprising. Referred to this page in 3 of the 5 games at Dark Star and each time it was if the player was reading it for the first time. You can tell if a player has read a rule before. Usually they give it a cursory glance for the rule they are a looking for. If they haven't they become extremely quiet and focus on just the rule. The picture provided on page 75 is a vast improvement from 40k5 pg 62 when describing how a vehicle gets a 3+ cover save