New expansion announced a bit ago, by the way.
http://us.battle.net/hearthstone/en/blog/18140859/blackrock-mountain-a-hearthstone-adventure-announced-at-pax-east-3-6-2015
Grim patron looks like a load of fun and the hungry dragon seems pretty radical as well.
I made a thingy which tested some probabilities comboing the grim patron with certain cards.
Spoiler
Testing "Bouncing Blade" 50,000,000 times. Produces 2 to 6 Grim Patrons.
2 patrons: 8,332,598, which is 16.67% of the total.
3 patrons: 8,330,820, which is 16.66% of the total.
4 patrons: 7,916,116, which is 15.83% of the total.
5 patrons: 6,529,813, which is 13.06% of the total.
6 patrons: 18,890,653, which is 37.78% of the total.
Testing "Mad Bomber" 50,000,000 times. Produces 1 to 4 Grim Patrons.
1 patrons: 14,813,256, which is 29.63% of the total.
2 patrons: 17,963,813, which is 35.93% of the total.
3 patrons: 13,054,576, which is 26.11% of the total.
4 patrons: 4,168,355, which is 8.34% of the total.
Testing "Madder Bomber" 50,000,000 times. Produces 1 to 6 Grim Patrons.
1 patrons: 4,385,830, which is 8.77% of the total.
2 patrons: 9,563,450, which is 19.13% of the total.
3 patrons: 13,299,076, which is 26.60% of the total.
4 patrons: 11,839,274, which is 23.68% of the total.
5 patrons: 7,291,489, which is 14.58% of the total.
6 patrons: 3,620,881, which is 7.24% of the total.