JayCee notes that the institution that he works for, a university, allows one to run a business on the side. My employer would most definitely not allow it. I think that even if I were to run a business in my spare time (i.e. outside working hours) that is somehow related to the work that I normally do, this would still not be allowed.
So now I am wondering, if you run your business from campus how do you bill the hours? Does the university get some fee/tax from you?