Today, for the first time since a World Series that somehow seems more intense today than it even was at the time -- and it was very, very intense then! -- the Los Angeles Dodgers will host the Houston Astros in front of actual fans at Dodger Stadium, which you can watch free on MLB.TV at 10 p.m. ET. And it’s fair to assume these fans will have many thoughts that they will be eager for Astros players to hear. It’s the next chapter in a rivalry that, in the span of four seasons, has become one of the fiercest in all of baseball, and really all of sports.

You can expect fireworks to fly -- wait until Joe Kelly pitches -- but then again, that’s the case with a lot of baseball’s best rivalries, both classic ones and newfangled ones. Some teams have rivalries between different players; Javier Báez and Amir Garrett are going to be connected to each other for the rest of their careers. Some have geographic ties, some have developed seemingly overnight and some have been going on for more than 100 years.

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In honor of tonight’s Dodgers-Astros game, here’s a look at the four of the biggest rivalries in three different categories: Classic, Geographic and Recent Heat. The latter category encompasses the kind of rotating rivalries that pop up now and again. (Remember when the Rangers and Blue Jays used to hate each other?)

CLASSIC RIVALRIES

4) Mets-Phillies
This one has had legs for decades -- heck, they’ll both always claim Tug McGraw -- but has become particularly fired up over the past 20 years, when both teams were excellent for extended periods of time. (Remember how much Jimmy Rollins and Chase Utley used to gall Mets fans?) It may seem a little cooler of late, but it probably shouldn’t: They are, after all, 1-2 in this division and will face each other a ton down the stretch.

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3) Cardinals-Cubs
There’s still a clear gap between 1-3 and 4 in this foursome, and the order of the top three tends to alternate. Both these teams are having down years in 2021, and the Cubs appear to be starting over entirely, but for the past 10 years, this has been an absolutely riveting rivalry. The Cardinals dominated the Cubs for many years, but the 2010s were the time for the Cubs’ charge, culminating in their 2015 NLDS shellacking of the Cardinals and, of course, their 2016 title. These are two of baseball’s signature franchises, forever connected.

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2) Dodgers-Giants
This season may end up being a new peak in the 100-year-plus battle between these two franchises, which of course once were rivals in the same sleepy East Coast town. They very well might be the best two teams in baseball right now, but only one can win the division. The Dodgers have owned the NL West for quite some time, but no Giants fan will let them forget that they have three titles this century as opposed to the Dodgers’ one. Will one of them have more bragging rights this year?

1) Yankees-Red Sox
Sure, it hasn’t really been top-shelf Yankees-Red Sox for a few years, which is to say it has gone from easily the best rivalry in baseball to just comfortably the best rivalry in baseball. It may never get any better than it was in 2003-04, when it felt like some sort of centuries-long blood feud … but it will always be must-watch baseball, even if neither team is good. Not to worry, though: They’re almost always good.

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GEOGRAPHIC RIVALRIES

4) Astros-Rangers
Texas is obviously a massive state, but it still never quite feels big enough for both of these teams. They were in separate leagues until the Astros moved to the AL West in 2013, but there was a healthy animosity even before that. Astros fans have had the bragging rights for the past decade, but the Rangers, uh, have a few more boosters nationwide in this rivalry than they used to, even without the on-field success.

3) A’s-Giants
The Giants take all sorts of justified pride in their three World Series titles since the move to San Francisco, but it’s the A’s who have won more games -- a lot more games -- over the past 20 years. Of course, so much of this rivalry is about the Bay itself, about how different Oakland and San Francisco are, and how different, of course, their stadium situations are. The A’s are a little scrappier, the Giants a little more Silicon Valley. But they’re both almost always terrific, particularly lately.

2) Cubs-White Sox
Most of these geographic rivals have a big brother-little brother dynamic, and this one is no different: Even when the White Sox win the World Series, like they did in 2005, people pay more attention to the Cubs. The White Sox sure look like they’re going to have the field to themselves for a while, not that it’s going to stop people from flocking to Wrigley anyway. And talk about your celebrity fans: The White Sox have Barack Obama, and the Cubs have Bill Murray. Choose your fighter.

1) Mets-Yankees
The ultimate little brother-big brother, there still isn’t a Mets fan alive who won’t remind you that the Mets ran NYC in the ‘80s. That seems like a tough haul today, but either way, these are two massive franchises that sure feel like they’re going to meet in another Subway Series Fall Classic someday. Everything either one of these teams does shakes up the rest of baseball. Imagine what happens when they run into each other.

RECENT HEAT RIVALRIES

4) Braves-Marlins
Let us not forget that these were the two playoff teams from the NL East last year. But the recent ill will here can be tied to the Marlins’ unfortunate, and consistent, habit of hitting Ronald Acuña Jr. As a hitter, Acuña has dominated the Marlins, and they have responded by being a part of an ever-growing series of brawls with the Braves, seemingly every series they play. With Acuña out the rest of the year, this feud is taking a break, but it will surely spark right back up in 2022.

3) Red Sox-Rays
Speaking of fights, I know a friend of mine who has the picture of James Shields trying to punch Coco Crisp during a fight in 2008 as the desktop on his computer. For two teams that are constantly overturning their rosters, the bad blood between the Sox and the Rays is always a little bit on boil, and it can’t help but be turned up this year with the two teams fighting for first place in the AL East. The only thing that bonds these teams and their fans is, of course, hatred of the Yankees. (And you could argue that the Yankees and Rays deserve a spot here as well.)

2) Dodgers-Padres
Perhaps the most fascinating recent rivalry. The Dodgers have been pounding the Padres for years, but now, San Diego clearly has had enough of it. The Padres have directly targeted the Dodgers, both on the field and off, and it has resulted in some truly incredible games the past couple of years. Both teams have pushed each other to be great -- their bidding war for Max Scherzer was only the most recent example -- and we are all the beneficiaries. If they end up playing in an elimination Wild Card game, look out.

1) Astros-Dodgers
Yep, this is the big one, and right now, it might be the biggest one. And forget just tonight: These are both playoff teams. Can you imagine if they met in the World Series again? (It actually almost happened last year, but this year there would be home games and home fans. Mercy.)