Since some verbals -- in particular, the gerund and the infinitive -- can act as nouns, these also can form the nucleus of a noun phrase:

Ice fishing is a popular winter pass-time.

However, since verbals are formed from verbs, they can also take direct objects and can be modified by adverbs. A gerund phrase or infinitive phrase, then, is a noun phrase consisting of a verbal, its modifiers (both adjectives and adverbs), and its objects:

Running a marathon in the summer is thirsty work.

I am planning to buy a house next month.