Just entering and exiting. You could ride and transfer all day long for a single fare as long as you never went through an exit gate, which I’ve actually done a few times in the past (at the time I was very poor, very bored, and had no AC).
Rail-to-rail transfers are free, as long as you don’t exit any station. I haven’t done a rail-to-bus transfer in a dog’s age. You used to have to pick up a paper transfer voucher before you left the train station to get a free rail-to-bus transfer. I think it’s all done on SmartTrip cards now. Do the buses even accept cash anymore?
BTW, you must have a SmartTrip card to exit a Metro parking garage. A few stations sometimes have human garage attendents to accept credit card payment, but that is rare. Why they couldn’t have set up the parking garages to accept regular Metro farecards is a mystery to me.
A SmartTrip card also saves you 25 cents per trip. Get a SmartTrip card!
BTW, slugging is a good alternative, and uniquely DC area. 
They do and they always get the stinkeye, from me at least, because they’re the people who are constantly holding up the line. Even more annoying (and time-eating) are the people who have to add fare to their card with the bus fare machine. The driver has to basically do it for them every time, while driving.
Some Metro garages now have credit card readers you can swipe yourself, but not all. The better alternative is just to make sure you’ve got the dough on your card.
–Cliffy
This. If you’re boarding a bus at a metro station, it’s far better to add money to your card in the station than on the bus machine.
Something that happens every so often–when you’re on an uber-packed car and stop at a station, people who are jammed right up against the doors (but aren’t disembarking at that station) will step out and to the sides of the doors quickly. If you’re one of the people waiting on the platform, the unspoken rule dictates that the stepper-outers get back on the train first.
If your employer offers SmartBenefits, use the program–this is a pre-tax paycheck deduction that you then load onto your SmarTrip card.
DC’s metro is indeed monorail-esque. rarely smells like pee, homeless at a minimum, and when it breaks down? they have shuttles! lots of shuttles!
i love the DC metro and i fear that if i move to a different city i’ll be too coddled to make the adjustment.
You know I found the signs confusing at first. They are on these posts that stand upright, 45 Degrees off the flow of traffic. I don’t know, now that I understand them, it seems obvious, but I do recall standing in front of them, quite baffled about which direction they were pointing.
DC’s stations all look ultramodern in a very late 60s way:
http://www.suite101.com/view_image_articles.cfm/2573052
My favorite Metro memory was this calm soothing voice, reminding Metro riders, to throw out litter in trash cans, because, “You have nothing to fear from putting garbage in its proper place.” Uhhh… ok. You know I wasn’t worried about the hazards posed by trash cans, but now I am. Plus you sound exactly like GLaDOS and now I’m starting to think the cake is a lie.
Also remember that eating and drinking anywhere in the system are prohibited. That’s one of the reasons it’s so clean. I don’t know how strongly it’s enforced now, but there was an infamous case where the Metro police arrested a 12-year-old girl for eating french fries.
It’s not actually a rule. It’s local custom. Metro has bent over backwards to avoid stating it as a rule, because they don’t want to have to enforce it.
I always thought it looked like the Death Star interior, in concrete.
My brother’s first job out of high school was working at a concrete factory that made some of the components of the Metro.
You have an awfully chary understanding of the word “rule.”
The directions of the trains are named after the last stop in that direction, just like bus routes. Make sure you know what the final stop is in your direction so you can get the train going the right way. For you, Largo and New Carrollton take you to Rosslyn and into the city while Franconia-Springfield and Vienna take you away.
In Rosslyn, the inbound traffic is on the top platform and the outbound traffic is on the bottom platform. This can be confusing sometimes because on the way to a destination on the opposite line, you come in on the top platform and leave from the bottom platform. You’d think, then, that on the return trip you’d do the opposite. But no. You don’t retrace your steps like that. You still come in on the top platform and leave from the bottom platform.
I, too, don’t ever worry about crime on the Metro unless it’s late at night or relatively empty. During normal commuting hours, it’s harmless…polite, even.
Don’t be the douche who gets on the train before everyone else and takes the spot right next to the just-opened door.
Where would you be commuting from, if you’re only taking the blue line 2 stops (and immediately transferring to orange)?
I used to slug, when I worked downtown. The challenges are finding parking (if you’re a rider), or finding riders (if you’re a driver); parking was quite limited at the spot I used, and if that was filled up, you had trouble in either situation. If I got out of the house in time, it was a dandy way to improve the commute. There are websites with a lot of suggestions on doing that. It’s been 10+ years since I’ve done so, however.
Metro stations are generally pretty safe, obviously there are incidents but as a percentage of total commuters, it’s pretty low. The Metro is also a LOT less disgusting than the NY subway - which has certainly improved but still has its smelly parts.
Now that I think about it, based on this statement from the OP:
I’m deducing he’s going from Pentagon to Clarendon, in which case it might be quicker (and cheaper) to take the bus (the 42, I believe).
Well, that’s a snarky comment that doesn’t move the thread forward. I was stating a fact that may not have been clear to someone outside the area.
“No eating and drinking” is a rule.
“Stand on the right” is a suggestion.
OMG YOU GUYS, I TOTALLY DID IT!!! 
And it was mostly a piece of cake. The train to the pentagon at tfe end of the day was uuuuubbbeeeerr crowded, so that was a little awkward, and it took me a moment to get my bearings as far as whether to be upstairs or down ( for the exact reason Chessic mentioned- I thought I could retrace my steps but I was incorrect ). Slugging was smooth and easy ( though really, it’s sort of weird sitting in someone’s car not talking for 30 minutes ), and I got to work and home in a timely manner. Thanks so much for keeping me calm and giving great advice! I made it in without any problems at all this morning, and am actually looking forward to this afternoon. The newness will wear off soon, no doubt.
DCnDC, I’m a girl, but otherwise you’re correct. I didn’t know there was a bus… Once I get the hang of the metro, I might have to look into that.
Time for work! Thanks again!
the first car is usually the least crowded car.
I think you’re overthinking this. Crime is not common on the Metro, and people take out their cell phones, Ipads, Iphones, Ipods, Kindles, etc., all the time.
You’re going to be riding with tourists, bureaucrats, IT workers, lawyers, lobbyists, and interns. There’s no reason to take pains to avoid eye contact.
I would be much more worried about catching respiratory illnesses from fellow passengers. That’s the real danger on the Metro.
The real problem with the Metro is that
(1) It’s too crowded at rush hour.
(2) Service is unpredictable. There are frequent breakdowns and unforeseeable delays. You won’t be able to reliably predict exactly when you’re going to arrive at work.
The system seems to have been designed without the consideration that large numbers of commuters would be using it. Thus, there are no bypasses and if one train is stuck, then every single train on the line is stuck.