When your wallet is empty and your credit cards are maxed out, there’s still plenty to do in Sin City

It happens. We have a blast spending money in the shops, restaurants and casinos (oh yes, the casinos) only to realize that our travel budget is shot. Sure, you can pull out the plastic, but in Vegas, you don’t have to. In fact, Sin City is teeming with free stuff to do and see after you’ve played that last chip.

FOUNTAINS OF THE BELLAGIO Grab a bench to view this stellar choreographed water show — consisting of more than 1,200 dancing fountains and a spectacular sound system — at the Bellagio. Shows happen every 15 to 30 minutes, depending on day and time.

CONSERVATORY & BOTANICAL GARDENS — BELLAGIO After the casinos, you’ll need a breath of fresh air (flower scented, preferably). The presentation in Bellagio’s 13,500-squarefoot conservatory changes five times a year and it’s open 24 hours daily.

PENNY AND NICKEL SLOT MACHINES Have fun blowing your last dime on the penny and nickel slot machines. Our favorites are those at the historic Golden Nugget and El Cortez hotels.

THE SIRENS OF T.I. — TREASURE ISLAND HOTEL AND CASINO Sexy dance moves. High dives. Sword fights. What’s not to love about a sultry pirate show, complete with pyrotechnics?

The man behind it is Kenny Ortega, director of “High School Musical,” so you know the choreography is hot. Open daily, with shows at 5:30, 7, 8:30 and 10 p.m. (weather permitting), at the entrance of the hotel.

FREEMONT STREET EXPERIENCE The Viva Vision canopy and light show near the city’s most historic gaming properties are the main draw downtown, where vintage Las Vegas and high-tech entertainment meet.

VOLCANO AT THE MIRAGE Fire, music, choreography … the Mirage volcano has everything but pirates. Every hour after dusk, the Mirage volcano erupts for the masses, all for the grand price of … nothing.

DUELING PIANO SHOW — NEW YORK-NEW YORK HOTEL There are many free lounge shows in Vegas, but the dueling piano show at the Bar at Times Square is one of our all-time favorites.

From top to bottom: The Mirage Volcano; the Fountains of Bellagio; the Bellagio Conservatory and Botanical Gardens.

BIG ELVIS — HARRAH’S LAS VEGAS PIANO BAR Vegas is overflowing with Elvis shows, but Pete Vallee’s “Big Elvis” is among the best. The hour-long show runs three times a day, four days a week.

NEON MUSEUM What would the strip be without neon? This open-air museum downtown was created to preserve some of the coolest pieces of Vegas history.

RIO MASQUERADE IN THE SKY Exotic, sensual and eclectic, this show at the Rio Hotel and Casino is like a carnival ... in the sky. It’s got jaw-dropping aerial performances, stunning dancers and fantastic music. And at $0, the price tag doesn’t hurt, either.