Originally hailing from North Africa, harissa is a fiery hot sauce as ever-present in the Maghreb as ketchup is on American tables. That being said, any further comparisons to ketchup (other than noting that they're both condiments) are almost outright offensive.
Varying not just from country to country, but one ethnic group to another, a sojourner in the region would encounter many different styles of the famed hot sauce. However, mainstays at the harissa party include hot red chiles, coriander, and olive oil. Easy enough, right? So, why don't you give it a try?