Formats often played at The 9th Zone!

Typical Tournament Formats:
Constructed
Constructed formats require that you have a deck already made when you register for the tournament. Rules for how the decks are built will differ by format. Unless otherwise mentioned, decks must have 60 cards minimum with no more than 4 copies of the same card (excluding basic land).

Block Constructed - This format only allows you to use cards from a specific block of sets. For example, Time Spiral Block would only allow you to play cards printed in Time Spiral, Planar Chaos, or Future Sight.
Each block has its own banned list, which can be found at Wizards of the Coast.

Standard (Type 2) - This format only allows you to use cards from the two most recent blocks plus the current base set. Currently, this is Time Spiral Block, Lorwyn Block and Tenth Edition. Additionally, Coldsnap is also included in Standard. When Time Spiral Block rotates, so will Coldsnap.
Standard has its own banned list which can be found at Wizards of the Coast. There are currently no cards banned in Standard, though.

Extended - This format only allows you to use cards from Seventh Edition to Tenth Edition, and Invasion Block to Lorwyn Block. Extended has its own banned list, of course, which can be found at Wizards of the Coast. Because there are more sets allowed in Extended, the decks are usually better.

Legacy (Type 1.5) - This format allows you to use cards from every set. There is an extensive banned list, however. The complete banned list can be found at Wizards of the Coast. Legacy uses some of the most powerful cards in magic, and can be very fast paced.

Vintage (Type 1) - This is the most inclusive format in Sanctioned Tournament Magic. You may use cards from any set, and the most powerful cards are restricted, meaning you may only play with one of each. There is also a banned list, and both lists can be found at Wizards of the Coast. Vintage is by far the most powerful and fast format. Turn one victories are common.

UNUSUAL 9th Zone Tournament Formats:
Constructed

Creature Feature - This is a very fun format that focuses on creatures of a certain type. Similar to TRIBAL (a casual Magic Online format), you must choose a specific creature type on which your deck focuses (like Merfolk or Knights).
RULES:

You must have at least 20 creature cards of the chosen creature type
You cannot play cards that ask you to name a creature type
You cannot play with cards that specify a creature type unless it also mentions YOUR creature type

Clarifications:
(1) The 20 creature cards must all have the specified creature type. They CAN be creatures with Changeling or Mistform Ultimas.
(1) Tribal cards do not count since they are not creature cards.
(2) Cards that cause you to name a creature type are banned (e.g. Distant Melody or Door of Destinies).
(2) Cards that have effects based on creature types are NOT banned (e.g. Coat of Arms).
(3) A great example is Tividar's Crusade (Destroy all goblins). Unless your creature type is goblins, you cannot play Tividar's Crusade.
(3) You CAN play cards (or even creatures of a different type) if they also mention YOUR chosen type. For instance, if you choose Kithkin as your type, you may play Cloudgoat Ranger, even though he is a Giant, because he puts Kithkin tokens into play (and also because you can tap Kithkin for his ability).
(3) Creature types mentioned in Reminder Text or Flavor Text do not count (e.g. Coat of Arms)

MORE FORMATS TO COME

Including: Mortal Combat, Peasant, Elder Dragon Highlander, AND MORE!