So this is a pretty cool game. BF read about it on Wikipedia and got hooked, and now he's convinced me to start playing.
It's a 3D RTS from EA. Used to be $50 plus the cost of booster packs, but the game is free to play now. You don't NEED to buy booster packs or points (which allow you to get better cards to use in combat) to enjoy the game, though.
If you like the RTS genre, I'd highly recommend checking it out. They've got a rad random map generator that's still in beta (so you don't get any rewards from it) that makes quick gameplay pretty easy. The rest of the maps vary in the number of players recommended for gameplay.
Also, the characters say funny things. One of the teams of skeleton archers I have make lulzy references to Monty Python movies.