A thought has crossed my mind to possibly start a mobile ( specific type) of food/beverage service at local sporting events. This would entail a booth and then the equipment.
I know I would need a mobile food liscense, but I don’t know all the specifics of everything else.
This would be extra curricular and I would shift my hours at work for Friday and Saturday and Sunday stuff.
It is a thought that just flared into my head and any suggestions would be welcome.
I would call your county health department and ask them for information on becoming a concessionaire. Every county is different, but I know some of them are very particular regarding what equipment you must have. They can also give you guidance on what inspections you will need to start with, and what you will need on an ongoing basis.
You may also need a business license, (some places call it a “privilege license”), you can call your city or county to find out what’s required. You’ll need to find out about setting up a sales tax account with the state, and it wouldn’t hurt to talk to a CPA and/or attorney regarding the best type of business to set up. (i.e. LLC, Incorporation, sole proprietor, etc) You can also ask the attorney about any liability insurance you may be required to carry.
There’s usually a lot of information on the website of your jurisdiction, but most places are really friendly and helpful when you call.
I’m wishing you the best of luck with your new endeavor!
Also, I’ve heard people love food on a stick when they buy from concessions… don’t know if it’s true, but it seems right to me! 
Are you preparing the food on site or at a central kitchen and delivering to the place where it’s being sold?
And **Dusty Rose **is correct, the health department should be your first stop because ultimately they will have the final say so you might as well do everything according to their wishes the first time around.
Uh … can you cook at all?