The average CMC calculated by the site is 1.1, but it's wrong. It's actually 0.9. The premise behind this is very simple: drop cheap creatures, buff them with cheap enchantments. The power doesn't come from the creatures. It comes from the enchantments. A single dual land is enough to run the deck pretty effectively. Two lands is devastating. The deck is incredibly fast because everything is so cheap. Give it a playtest and you'll see what I mean.
Edit: Wow, people seem to really like this deck, so I guess I'll type out a better explanation for my card choices.
Ethereal Armor - This card is the whole point behind the deck. With all of the enchantments you're putting out, this little guy gets massive.
Kor Spiritdancer - The secondary point of this deck. Costs more to play than anything else in the deck, but it's worth every bit. The +2/+2 alone is genuinely terrifying, but the draw mechanic in addition to that makes this card completely insane.
Memnite/Ornithopter - They cost 0, so you don't waste your precious mana getting out an enchantment host.
Aqueous Form
- Getting blocked kind of ruins any plans of doing damage. This circumvents that. The scry is nice too. Combos nicely with Curiosity.
Sigil of Sleep
- I can't tell you how many games this card has won for me. This plus
Aqueous Form
is devastating.
Curiosity - When you're dropping cards this fast, you need a way to replace them or bigger, more expensive things played by other players will win the arms race.
Hyena Umbra
- Gives a little boost and a bit of staying power against any surprises that might otherwise kill your creature.
Shimmering Wings
- Flying for 1 and can be returned to your hand if it's about to get removed or something. Interestingly, it can combo with Kor Spiritdancer's draw ability if for some reason you have a whole bunch of mana to spare. Combos even better with two of them.
Slippery Bogle
- A hexproof guy for 1 is incredibly useful, as removal is the primary downfall of this deck.
Swords to Plowshares - Removes any creature, costs 1. Perfect.
Unstable Mutation - Don't let the -1/-1 counters fool you, this thing is great. It will be 4 turns before you'll see a net loss in power. 4 turns with this deck is like 8 turns with a normal deck.
Emerge Unscathed - Replace Swords to Plowshares when playing against decks that run really heavy removal.
I've really enjoyed building and playing this deck so far. Thanks for stopping in for a look. Any suggestions for improving this thing are welcome, but keep in mind that I'm extremely unlikely to consider anything that costs more than 1. If a card costs 2, I'll consider it if it basically says "you win the game" like Kor Spiritdancer does. 3 won't be considered unless it also gives me free pizza.