The Comcast Center, second left, in Philadelphia. (Matt Rourke/ASSOCIATED PRESS)

Ah, the ambiguous days of summer. The lines between weekdays and -ends become blurry, and we have a pass for making any day of the week a play day. It was with this in mind that I decided to do something wacky: I planned a weekend getaway to Philadelphia smack in the middle of the week.

I rounded up my get-outta-town girlfriends, and on a Wednesday morning, we headed northinto Philly. Over the next 30 hours, we discovered a city that more or less belonged to us. We found ourselves alone in a museum, befriended bartenders and shopkeepers who had nothing better to do than share their life stories with us, stumbled upon some sweet weekday-only deals and happenings, and never waited for a drink or a table. Our only regret: that we hadn’t also been there for Monday and Tuesday.

After we’d checked into our hotel and had lunch, we walked through Rittenhouse Square to the Rosenbach Museum and Library, which just opened a year-long exhibit on Maurice Sendak’s work. If you’re searching for a place to stock up on terrific “Where the Wild Things Are” merchandise, the museum’s gift shop has it all.

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More walking and window-shopping led us to wine bar Tria for weekday happy-hour specials, where we enjoyed a total of three drinks and a cheese plate for $20. We sat at a sidewalk table and tried to plan our night. I had printed out an ambitious list that I only later realized would take a month of weeknights to cover; there’s a lot going on here during the week. For starters, there’s movie night at the historic burlesque Trocadero Theatre on Mondays; the Erotic Literary Salon at the restaurant and whiskey bar Time once a month on Tuesdays; movie night at Nomad Pizza on Wednesdays; a drag show at Bob & Barbara’s Lounge on Thursdays; and happy hour every weeknight at Barcade, a bar where you can play classic ’80s arcade games for 25 cents a pop.

We decided that more cheese would help us figure out what to do with our evening. So we ate dinner in the tiny enchanted courtyard of Wedge + Fig in Old City, not far from the Liberty Bell and Independence Hall. Here, we faced more decisions: havarti, Gouda, Manchego, gruyere, brie, cheddar or fontina on the build-your-own-grilled-cheese sandwich?

After dinner we walked to National Mechanics for the tail end of trivia night. The bar is in a beautiful old bank building, with glowing, fox-like taxidermied animals hanging from the ceilings. A bartender named Evan served our drinks in glasses stamped with pictures of Philly characters like former mayor Frank Rizzo and Rocky Balboa. I got serial killer Gary Heidnik.

Evan told us that the bar holds science talks every second Monday of the month (mating habits of giraffes, anyone?) and karaoke every Tuesday. He said that weekdays at the bar are a different animal. “Sunday through Thursday, you get people who live and work in the neighborhood,” he said. “Friday and Saturday, you have college kids, people from New Jersey, and generally people who just come to drink.”

We invited Evan to join us on our hot pretzel adventure that night — Center City Pretzel sells them right out of the oven when it opens at midnight. But his shift lasted until 2 a.m.

To kill time before midnight, we went to Sugar’s, a basement dive bar in an old sugar refinery. We were the only ones at the bar and were happy to find a $3 burger weekday special, even though we were far from hungry. The two bartenders entertained us with a conversation about their bands, which they described as “super-punk” and “post-punk.”

Past South Street, we walked at a fast clip (regretting that we hadn’t cabbed it) through a gritty neighborhood, en route to our hot pretzels. When we arrived, the garage door was open, and the bready smell was so seductive, I expected to see it wafting out of the building. A guy named Chris, in a Phillies T-shirt and cap, offered us a quick tour. We got to see 19,000 machine-twisted dough pretzels in the freezer and the 13-minute path they take in the oven. Most are sold to street vendors and schools. Chris told us that you need a chemical to make the pretzels brown. “They don’t bake that color,” he said, “naturally.”

We took our bag of perfectly browned hot pretzels, hailed a cab and headed to our hotel. The cab driver was seduced by the pretzel smell, too. As we paid him, he shamelessly asked whether we had any leftovers. “Nope,” I said.

The next morning, we grabbed some morning brew and walked to Philadelphia’s tallest and newest tower, the Comcast Center. I wanted to see the lobby video wall, which is supposed to be the world’s largest LED screen. We stood there, transfixed, watching amazingly clear and artsy video snippets — from a space shuttle launch to a quirky bit that made it look as though people were climbing up the lobby wall. Then we spent a few moments feeling smug about being in an office building on a weekday and not having to work, while all the workers floated through security without a glance at the amazing screen.

Our next stop was the Free Library of Philadelphia, which offers a tour of its rare book collection every weekday at 11. The guide picked up a small brown clay piece that looked like a thick graham cracker: It was a 5,000-year-old cuneiform tablet. She said that the writing on it documented a trade of sheep for goats. Then she unfolded an ancient triptych that contained panels of an Egyptian papyrus leaf scroll. Leaning in to look at the plastic-covered pages of hieratic script, I found that they oddly resembled three flat screens. I felt a little embarrassed that in such a place I was thinking that this venerable piece looked like a Kindle.

We hopped onto the bus back to Old City, where we checked out the funky independent shops that line Third Street. There’s a vintage shop that sells by the pound (Sazz Vintage), a boutique with a custom line of men’s button-down shirts with vintage buttons (Franklin Square), and a cool clothing shop/gallery that has monthly exhibits on such eclectic things as surfboards and urban backyard chicken-raising (Art in the Age of Mechanical Reproduction).

Alas, the clock was ticking on our weekday pass. As we were packing up at the hotel, I looked out our 19th-floor window. Down below, the city bustled with workday activity. On the sidewalk, I saw a tiny awning covering an itty-bitty cart. And I laughed, thinking about our strange midnight adventure and wondering where the vendor bought his soft pretzels.

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Kaplan is a freelance writer in Washington. Visit her Web site is