Tony Hawk's Pro Skater 2

Complete career mode to unlock the following. Beating career (3x) means you have to beat it with three different people to get that bonus.

When entering codes, begin playing, then pause the game. Some codes will only work in Career Mode. Hold L1 while entering the following codes.

At the Main Menu hold L1 and press Up, Up, Up, Up, X, Square, Up, Up, Up, Up, X, Square, Up, Up, Up, Up. The wheel that the options are set on will turn. Now begin a game in any mode. (This is a good way to get those hard to reach cash icons and near-impossible high scores in Career Mode.) Whenever you are skating. Ollie by pressing X, and then press X once more while you are in mid-air. This will cause your skater to rise into the air. If you hold Triangle you will hover. Use the DIGITAL PAD to move your skater in the directions. You can do tricks in the air while you are floating as well. When you land, the game will add up your points.

Bring up an unbought board for the skater you're playing as. Press Up and X or Down and X together to get board designs for the skater next on the list, or previous on the list, respectively. The game will ask if you want to spend a certain amount of money to buy the board. Choose yes and no money will be deducted, but you will now have the board design available. To choose which board you get, simply bring up the skater's whose board you are trying to access board selection, and bring up the board you want. This trick does not increase your board stats.

At the main menu hold L1 and press Up, Square, Square, Triangle, Right, Up, Circle, Triangle. If the code was entered correctly the wheel will so a 360 spin.
Then enter the Create Skater menu and type in one of the following names as the skater's name to get that person.

Connor Jewett
Edwin Fong
Jeremy Andersen
Silvio
Aaron Skillman
Hudson
Kage
Nggdynln
Robert Earl
The Pouncer

The gym is a hidden area in the School II Southern CA level. To open the door which leads there you must do the Roll Call! Opunsezmee Rail gap 20 seconds after you've started the level. The only to achieve this is by taking a right turn when you start the level and going down the hallway. When you come out of the hallway take a hard left turn and head to where you enter the entire stage area. There you will find a rail between some stairs and a slope. You need to grind this rail at about 1:40 minutes and do the gap in order to open the gym doors.
Inside the gym you will find a pool and a bascketball court and a few other gaps.