A project is an undertaking. The scope and difficulty of the undertaking varies: we all have a backlog of little projects around the house that we intend to tackle come the weekend, which seem trifling compared to public works projects that a city might undertake to upgrade infrastructure. An especially important or difficult project or one that requires a certain boldness or energy might be called an enterprise: The mayor added that keeping the peace is a difficult enterprise. This noun is also used to refer to the boldness or adventurous spirit with which such projects or activities are undertaken (the founders showed great enterprise in securing funding), and to companies or businesses themselves, complex commercial undertakings that they are (local enterprises made up a large share of the sector). 

Let’s sort out the difference between these two adjectives: when a set of things is described as assorted, it usually means the set consists of different or various kinds, but that all kinds belong in the same broad category (assorted flavors; assorted crackers). When something is described as miscellaneous, a lack of order or commonality is emphasized—and randomness may be implied. In a miscellaneous set, things of different kinds or natures are mixed together (a book of miscellaneous essays on American history). Each item may be in some way different from all the others (a miscellaneous assortment of furniture), or not fit into an existing classification (miscellaneous expenses).

We’ll try to keep this simple: the adjective complicated can be used to describe things that are very intricate and complex (a complicated apparatus for measuring brain functions) or things that are difficult to  understand or explain (a complicated subject). The synonym convoluted is most commonly used to describe stories, plots, or thought processes that are difficult to follow and perhaps even a bit dizzying in all their twists and turns (a convoluted way of describing a simple device). The word’s still-current literal meaning, after all, is “coiled” or “twisted.” There are good reasons a snail’s shell is convoluted, but in the more common, figurative use of convoluted, the word often suggests that something is unnecessarily complex or complicated to a fault.