Hungry guest:
Enter Tony Day as a guest name. This guest will usually be hungry or very hungry.

Photographer guest:
Enter Chris Sawyer as a guest name.

Artist guest:
Enter Simon Foster as a guest name.

Increase guest happiness:
Enter Melanie Warn as a guest name. You can rename the guest to another name and repeat this on another guest as needed. Keep doing this to also increase your park's rating.

"Wow!" thinking:
Enter John Wardley as a guest name.

Guest pays double entrance fee:
Enter John Mace as a guest name.

Faster Go-Karts:
Enter Damon Hill as a guest name. Enter Michael Schumacher as a guest name to race even faster.

Slower Go-Karts:
Enter Mr Bean as a guest name.

Multiple names:
You can have more than one person with the same name (which works well when using the cheats) by changing the capitalization of various letters. For example Chris Sawyer can be used on another person by making all letters lower or upper case (chris sawyer and CHRIS SAWYER).

Guests never leave:
Put a "No Entry" sign by the entrance, facing away from the entrance. Guests can still come in, but will not leave. Note: This may cause your park rating to decrease, because many guests will be "lost" and want to go home.

Extra building space:
Build a ride or attraction such as a maze. You can now build on top of that with smaller rides (for example, bumper cars).