The slot machine cheat is complicated and random, but it could be worthwhile and it's definately interesting. To set it up, do the following:

1. Place a marina and power it.
2. Go to Budget/City Ordinances.
3. Turn on Legalized Gambling.
4. Highlight the sailboat and press the Left Shift button.
5. If the previous steps are completed correctly, there is a 25% chance that a slot machine will appear.

Each play of the slot machine costs $10. What you win depends on whether or not you have disasters on.

If you have Disasters on, you could win:

• A 95% chance of winning money (5% of the your total current funds) or a 5% chance of losing that much.
  
• Random destruction of property: Simulator chooses a random spot on the map and blows up whatever is there.
  
• Renewal!: All rubble in the city is replaced with trees.
  
• Random destruction of property: Simulator chooses a random spot on the map and blows up whatever is there.
  
• Random fire: Starts a fire.
  
• Power plant renewal: The oldest power plant in the city has its age set back to zero.
  
• Mixed bag: If a fire is currently burning in the city, it will be put out and replaced with a flood.
  
• Tornado: Starts a tornado if one isn't already going.
  
• Mystery!: The remaining two wins are surprises.

If you have Disasters off, you could win:

• Jackpot: A 95% chance of winning money (1% of your total current funds) or a 5% chance of losing that much.
• Renewal!: All rubble in the city is replaced with trees.
• Power plant renewal: The oldest power plant in the city has its age set back to zero.