The Diner Right on Campus
Tamber's is located very close to the JHU campus (thus, it's in Baltimore); basically right across the street from Wolman Hall and McCoy Hall. It serves American and Indian food in a faux-50s kind of atomosphere (which I do not particularly enjoy). They're open seven days a week, from 11 AM until 10 or 11 PM.
Their American food is almost universally mediocre. For example, just this afternoon, I went and ate a hotdog (covered in chili) as part of my initiation into Discordianism. The roll was unheated (so it fell apart from the chili) and the chili was uninspired, reminding me of something that was probably given to me in an elementary school lunchline. I should have been smart and went to Attman's Deli. The hamburgers are decent enough, but at only 8 oz, you're paying way too much for them ($6.50). I've heard mixed good and bad reviews from various people about the shakes and malts; it may depend on who is making them that day.
After that, you might think I was panning the place. But the Indian dishes are simply divine. As a heterosexual white male, I do not use the word "divine" often in describing something, so take the hint. Their Saag Meat (big chunks of lamb covered in creamed spinach and coriander) is so very good. For the vegans and vegetarians out there, you can also get Palek Paneer, whcih is basically what is described in the Saag Paneer writeup (why the differences in naming, I'm not sure). The menu is fairly wide, and considering the amount of food you get (a lot), the prices are good ($8-$12). There is also a deal where, if you order two Indian dishes, they charge you $18 even (regardless of the normal price of the dishes, so you may end up paying more than you would normally if you order the wrong things), and they'll throw in some tasty nan bread for free (this deal is for take out only!).
I recommend take-out, because, as I've mentioned, I'm not a big fan of the dining room there. Also, the prices are significantly higher for dining on the spot versus getting take out. Don't ask me why, but it's true. Add on the tip, and it's looking a lot cheaper to get the food as take-out and eat it on the floor of your living room (preferably while watching Buffy or something).
There is a separate place you go to get takeout (on the north wall of the building). This is nice, because you order and then have a nice smoke while your food is being prepared.