A game I use to play (and be creamed at by my siblings) when I was younger, I only recently picked it back up. I am very happy I did, as I'm having a good time building decks and playing people around my area.
As of now, I play with a green ancient ooze/mana rush deck, and my main deck being a black Rats deck.
Now, I've been told by a lot of people rats are a bad deck to play-Yet I haven't had any problems playing this deck. It seems most people I play who try to roll giants like Akroma Memorials with beef creatures seem to get downed fast. My typical strategy with my rats is to rush early on, and when I get Marrow-Gnawer, I begin to multiply my rats.
To help multiplication of rats, I have Ratcathers, who allows me to pick a rat card of my choice from my deck into my hand. This means if I haven't gotten Marrow-Gnawer or Ink-Eyes yet, I can. The fear mechanic in this deck works well, playing other decks that cannot block any rats open the way for Ninjitsu summons on my ninjas. I carry a coat of arms, even though I know I should have something like a Door of Destinies instead, in my deck. When it comes time to multiply, I simply sacrifice a rat using Marrow-Gnawers ability, and I put X 1/1 tokens into play, X being the number of rats. As far are tournament laws are concerned, the next rat sacrificed may be a token. Let's say I had 5 rats, Marrow included. I sacrifice rat #2, and now I have 9 rats. Next turn, I decided to take out a token, and move myself to 16. Repeat, win by mass zerg. Add a coat of arms (Every creatures gets 1/1 for each creature in play it shares a creature type with), and I can swarm 106 105/105 rats. Add a Pestilence Rat (Is */3, * being the number of rats in play), and even if I face another weenie deck, I can send a single rat with a higher number and fear to deal the killing blow.
The only faults are genocide cards (Destroy all target creature types), and playing other rat decks get fun. The only other rat deck I played was a Relentless Rats, a coworker of mine had gotten pretty mad he was rushed and beaten by my rats. He constructed this deck (24 Relentless Rats. For those that don't know, there is no limit on how many relentless rats you may have in your deck, and they recieve 1/1 for each relentless rat in play). Using the logic that I would feed him, we had a stand off (With our rats being around 201/201) until I played a Pestilence rat. Being around 405/202 (I hardly remember), I laid waste to his defense and steamrolled him.
Now that I'm done being a geek. I suppose this opens discussions.