Prereleases are Sealed Deck format events, where you build a minimum 40-card deck using the contents of a themed Prerelease Pack (6 Shadows over Innistrad boosters and a Premium date-stamped promo card) plus basic lands that are provided to you by the store.
Saturday: 12:00PM & 5:00PM
Sunday: 12:00PM & 5:00PM
Cost: $25 per event or $110 for all five.
After your deck is built, you'll be randomly paired with another player for a best two-of-three match. Each round you'll report who won and be paired up with a new player. If you do well, you might win additional Shadows over Innistrad booster packs as prizes!