plants in smaller space, especially raised beds.
As for what to grow, the tomatoes and peppers will want the longest sun because they need heat and hot peppers are hotter with more sun on them. At the shadier end of the bed you can grow things that hate full on hot sun like lettuce, parsley, cilantro, and other soft stemmed herbs. Heartier herb plants like rosemary, basil, thyme, oregano, and tarragon can be dropped in any smallish sunny spot in the bed -- they also stand abuse in the form of less watering.
Tomatoes, most cukes and some summer squashes are vines, and that means that if you plant them near the edge of the bed and train them to trail over the edge you can place the cages outside of the bed rather than have all that bulk covering up good planting space.
Because DC has a relatively long growing season, you can start growing baby lettuces in the early spring by covering them at night. This can be done with a floating row cover rated for light frost or you can make or buy a small cold frame or mini-greenhouse cover. The same can also be used at the end of the season to protect a few plants from light frost, particularly herbs.
See here:
http://www.gardeners.com/Season-Extending/default/StandardCatalog.VegetableGardening_SeasonExtending.cat;pgid=Yfob4opu00000000000000000000AIXk_IoE;sid=74f__PDepN4X37eKkefe_vDURbV6PNH0V0w=The downside of covers is that someone must uncover them in the morning and cover them at night.