Jack's Boathouse LLC
This place is great for canoe and kayak rentals from the Georgetown area up and down the Potomac. It is very cheap, and you can go out to Roosevelt Island, the small island seen from the Kennedy center, etc. You can see many historical sites. If you go down river, and you can find the Kennedy Center, the Lincoln and Washington Memorials, Roosevelt Island, and the Watergate. If you go upriver, you can see the Three Sister's Islands and the remains of the C&O Canal System. Definitely a must-do for all tourists/students in the nice weather.
Bicycle Pro Shop
I took my bike in because I had a problem with the seat--it was very loose and actually came off at one point. I took it to this shop in Georgetown because it was the only bike repair shop in the area that I actually knew of, but I am definitely glad that I went. I ended up getting my seat fixed within 24 hours and they were courteous and helpful. Also, it was inexpensive. I would definitely recommend going here for bike problems.
Buffalo Billiards
I think this was actually voted one of the best in DC in Washingtonian magazine. All I know is that I had a great time there. They have a huge pool room with many, many tables, and the atmosphere is great. It has couches, two bars, and a bunch of jukeboxes. Definitely a good place to go with a bunch of your buddies.
Recessions Restaurant
This is a very strange place, which caters to only certain personalities. It is a bar in the basement of a hotel, and is very dim. It has pool tables, dart boards, a Golden Tee machine, a jukebox, etc. It has great happy hour specials with $3 king kong beers (26oz), and they only turn to $4 around 8 or 9 pm. They also have half price appetizers during happy hour. This is not a place to go if you want to meet people--it's alot of regulars and older people who to some may seem sketchy. But it's safe and fun to go with friends to drink for cheap or to just get away.
Filomena Ristorante Of Georgetown
I absolutely LOVED this restaurant when I went there--thought it was one of the best meals I've had in DC. But some friends I went with thought it was only mediocre. Either way, it has a large menu with a variety of Italian dishes, which I thought were amazing. It is pretty expensive, however. My advice would be to go once and try it, because it all depends on each person's taste.
Morton's The Steakhouse
This is an amazing steakhouse. It is located in Georgetown and has a great ambiance. It is very expensive, but definitely worth it. It has a large selection of menu items, and even the side dishes are delicious. They bring a small portable table to where you are sitting, and show you the different cuts of meat they offer, and even a huge lobster if you wish to order that. I've had the double fillet and the porterhouse, and both were absolutely amazing. My advice is to save up a little and go for the gusto with this steakhouse, becauase although expensive, it is one of the best meals you will ever have.
Sizzling Express
I love the Sizzling Express chain--it's great for students. Each store is set up with a hot and cold buffet, a sushi bar, a sandwhich bar, and an alcohol bar. They have happy hour specials on the alcohol, and they have a large variety of foods, some which are staples and some which change every day. If you get the buffet, you pay by the pound, so you have to be careful you dont get food that is too heavy or you'll be paying a boatload. Either way, it's great for a quick lunch, and the cashiers are QUICK, so even if it is packed, you never wait more than 2 minutes to cash out.
Famous Luigi's
This is an amazing restaurant. It is sort of small, two levels, but is capable of holding large (20+) parties. It is by far, the best italian food I have had in DC. The best part about it is that almost all of the entrees range between $10-$16. They also have a pretty decent wine selection, and it's great in the summertime when you can eat ouside on the patio. Definitely a must-eat.
Mc Fadden's Restaurant-Saloon
This is a great bar to go to on Tuesday nights because it has dollar drafts (used to be Yuengling and now its Miller High Life). It has a great college and grad school/young professional crowd. The bouncers are VERY strict though so don't try to use a fake ID or anything because you will be arrested. Other than Tuesday's it is pretty packed sometimes, but no real specials, so I usually only go on Tuesday nights.
Lulus Club Mardi Gras
Lulu's has gone a little downhill over the past few years. It used to have great happy hour specials--dollar drafts and and dollar appetizers. They have new owners or managers or something, and now its $2 instead of $1--still not a bad price. However, at night, the club is very hit or miss. Oftentimes, it has $10 cover charge for everyone, even patrons over 21, which I think is pretty lame. But, it is the largest club in DC, with over 5 dance floors and 2 levels, and if there is a big party going on, it might be worth it.