All the details it takes to start a business can be boiled down to a single one time offer that has a beginning and an end.

Marketing

Sales

Logistics

Personnel management

Legal stuff

Everything else

Think about all the details it takes to run a business. Boil it down to a one day, single event. Putting on an event where you have paying customers, and possibly sponsors, people you have to manage during the event; all will give you an insight into what it takes every single day to run your own business.