Going to St. Louis Labor Day weekend to mark gateway arch national park off our list. Besides that and catching a cards game, what are the must-do's? Staying downtown between the arch and Busch stadium with no car. Would also love some food recs.

Any kids?

If so, City Museum is a must do.
One of the best things about St. Louis is that there are a lot of free attractions.. the Zoo, the Natural Sciences Museum, the Science Museum and Planetarium... all are good, especially for families.
If your politics can stand it, Anhauseur Busch tour is entertaining.
Grants Farm is great and they give free beer.

There is good food in St. Louis, and I've been there many, many times, but honestly I'd not rate it really high on the dining compared to many other cities. Like any city you can find good food, though. There is a good Italian district, they locals will say "On the Hill" and there are several good choices there. Zia's is the one I've been that we have liked. Two local foods come to mind that you might want to try... Imo's Pizza.. I personally hate it. It's thin crust and with provel cheese, which I think is awful, but St. Louis loves is. And toasted ravioli, good appetizer that you can find on almost any menu. Not fine dining but Fitz's root beer factory is a fun place to eat in the University District. There is a great record shop across the street. Soulard is where you'll find the hip and trendy places that also have nightlife.

All good suggestions. My wife was born in St Louis, and so we have been there several times. Toasted ravioli is a great suggestion, as is the children's museum and the zoo.
Soulard and Dogtown have a lot of bars and restaurants and are fun. It's a city of neighborhoods, so just explore the neighborhood you are in.

Also, Ted Drewes frozen custard for dessert.

Previous posts have great suggestions.

You said you don't have a car, but if you have any interest in church architecture, I'd highly recommend stopping by the Cathedral Basilica of St. Louis. The interior is covered in glass mosaics. I read somewhere it is the largest collection of glass mosaics in the Western hemisphere.

I was in town for work a few years ago and had some time to kill before going to airport, so I decided to check it out. It's extremely impressive.

https://cathedralstl.org/

Ted Drewes is also a must.

Thanks for all the recs guys! Looks like it's definitely worthwhile to Uber to the zoo & natural science center right next to each other one day. And texag2001, I had already circled that church for mass on Sunday since it's 4 blocks from the hotel, but I'll be sure to show up plenty early

The Zoo is free but the attractions you may want to do are not included

If you have kids the City Museum is a must

Gateway Arch and Dred Scott courthouse are intertwined

Ate ribs here about five years ago. Pretty good.

Pappy's Smokehouse
(314) 535-4340

No kids in tow…just me and the Mrs. Is it worthwhile for adults?

You talking about City Museum?

Depends on what kind of adults you are. I'm 51 and I have a blast there.

Urban Chestnut Brewing Company is one of our favorites. It's a German bierhall, and the beer and food are fantastic. We've always gone to the one in the Grove, but there's a midtown location too.

If you live in the northern DFW suburbs you should try 5th Street Pizza in Allen. They have "St. Louis style" pizza, which is a thin crust pizza with the aformentioned provel cheese.

It is a very different cheese that is like a cross between american and cream cheese. I'd try it there before potentially wasting an opportunity to try something else in St. Louis if you don't like the style of pizza. When we lived in the area my wife and I would eat 5th St several times a year but only get a provel pizza once a year or so. It is good but...different.

FTR - 5th St has the best pepperoni rolls on earth - I only say that if you hate the SL style and use it as a reason to not return.

Otherwise I can't help - never been.

If you want great Italian go to Cunetto's.