The verbs gather and congregate are birds of a feather. Both terms deal with bringing or coming together. But gather, the more common of the two, is more often used to talk about bringing people or things into one group or place: after they got the tent set up, he went to gather firewood. Congregate is used to talk about people or animals coming together or assembling in large numbers: People waiting for rooms congregated in the hotel lobby. The difference between bringing and coming is key, since the former indicates a transitive verb and the latter indicates intransitive. The related noun congregation is mostly used in association with religious worship, but congregate has a broader range of application: you may hear of fish congregating near a reef or of people congregating in a park. Both terms come from a Latin verb meaning “to flock together.”

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).