If you provide singing telegrams, for example, you can knock on a person's door and claim to be a nurse, a police officer, or other profession as you flash your fake ID. Then, as the music starts and your performance begins, it will become quite clear that you are not really a nurse or a police officer.
You can also use a ID to help other people pull off a practical joke. If you are an actor or actress that is trying to break into the business, one way to get a bit of experience and to make some money until your big break is to offer your services as a professional actor. People looking to pull off a great practical joke generally need to enlist in the help of someone that the target doesn't know. If you can keep a straight face and think on your feet, you will be the ideal person to help someone pull off a great gag.
Of course, if you are going to hire your acting services out in order to help with practical jokes, you can't possibly think of all of the possible scenarios a person may wish to create for a practical joke. Therefore, you likely won't purchase a bunch of fake IDs ahead of time. Rather, you will have the fake ID created specifically for the job. At the same time, by hanging onto all of the fake IDs you purchase for each job, you might be able to provide on-the-spot services for a person that may not have the time to wait for a fake ID to be made. In addition, be sure to pass the cost of creating these fake IDs onto the person hiring your services.
There are certainly times when using a ID is not legal. For example, you cannot use a fake ID in order to get into a bar if you are not of legal age. Similarly, it is illegal to use a fake ID to purchase alcohol or cigarettes if you are not old enough to do so and you cannot use a fake ID in order to access areas that would be otherwise illegal for you to enter. Otherwise, it is perfectly legal to make and to have a fake ID. So, take advantage of your right to have a fake ID and use one - or many - to help spice up your act and put you in high demand!