A great chapter for descriptions of the kind of parties that Gatsby throws is chapter 3. On the one hand this account presents us with the social elite of the day who frequent his parties, but on the other hand, the behaviour of these people is characterised in terms of their vulgarity. At one stage, Nick comments that the guests conduct themselves "according to the rules of behaviour associated with an amusement park." This can be viewed as another paradox or disparity in the novel relating to the gap between pretension and reality.
However, at first, until Nick actually attends one of these parties, he is attracted by the sights and sounds:
In his blue gardens men and girls came and went like moths among the whisperings and the champagne and the stars.
Note the attractive onomatopoeia in "whisperings." Nick observes what goes on like an outsider, looking in and attracted to what he sees, even though a discordant note is perhaps set at the end of the first paragraph with a description of the work that is needed to be done to repair the "ravages of the night before" on Mondays.
However, the bright lights and glitter seems to overwhelm Nick in one sense. Consider the following description:
The lights grow brighter as the earth lurches away from the sun, and now the orchestra is playing yellow cocktail music, and the opera of voices pitches a key higher. Laughter is easier minute by minute, spilled with prodigality, tipped out at a cheerful word. The groups change more swiftly, swell with new arrivals, dissolve and form in the same breath; already there are wanderers, confident girls who weave here and there among the stouter and the more stable, become for a sharp, joyous moment the centre of a group, and then, excited with triumph, glide on through the sea-change of faces and voices an colour under the constantly changing light.
It is clear that Gatbsy's parties are immense, lavish affairs, with no expense spared. They are deliberately designed to attract the social elite, and yet interestingly, Gatsby remains an observer of the action, rarely participating in the raucous "prodigality" that is described.