If you'd rather not be a celebutante or a poor musician, you can also reject the daytime completely--and become a vampire. The vampires in The Sims 3 are less like Dracula (they won't burn up in the sunlight, for example) and a lot like Twilight (sexy and, um, always ready to party)--though they don't glitter. Becoming a vampire is actually a fairly easy task--just find and befriend one, and then ask them to "turn" you.
Finding vampires is a cinch--even though they reportedly hang out in the higher-end venues, you'll still find a couple chilling in the open-to-the-public clubs and lounges. You'll be able to tell who's a vampire because they'll have red eyes, and their picture will also show up with a glowing red border around it in your relationships tab. Vampires are pretty much like everyone else--just flirt shamelessly with them and they'll warm up to you pretty quickly. Once they've taken a liking to you, you can ask them to "turn" you--they'll usually do it, so long as you're in a semi-private place (if they tell you they'd rather wait until the two of you are alone, just invite them over to your place later on).
Vampires can do some pretty cool things--like hunt for Sims to feed upon. Of course, once your vampire Sim wants to eat--er, turn--someone, they have to convince the other Sim to let them do it. Vampire Sims also have mind-reading capabilities to help them convince people--they can see someone's entire list of traits immediately, and use that knowledge to befriend them. Vampires' weakness is, of course, the daytime--while they won't burn to a crisp at the first glance of sunlight, but they grow tired quickly in the daytime.
The Sims 3: Late Night is a great expansion pack if you've been waiting to move your Sims out of the suburbs and into the city, with just one problem--your Sims actually can't "move" out of the suburbs and into the city. That's right, any Sims that you have living in Sunset Valley can't be moved into Bridgeport--which is unfortunate, of course, if you have a Sim or two that you've grown fond of. No, instead you'll need to create entirely new Sims to live in the new city, and there won't be any cross-interaction.
Another minor annoyance is the fact that, for all of the high-rise apartment buildings with elevators, multiple floors, and tons of unopenable doors, it doesn't appear that you can move more than one Sim/Sim family into a building. As a design shortcut it makes sense, but it's still weird that every apartment building has exactly one apartment.