DC is great. However, if you want to see/do everything I would make it a weekend trip. The traffic can be a pain, but I reccomend parking and taking the metro in if you can get away with it. Parking is hard to find. If you go to the zoo, especially with kids…make sure you take lots of sunblock in the summer months and bottled water because food & drink in the zoo is expensive, and be prepared to walk – alot – uphill too. The museums are great, as well as chinatown, and arlington national cemetary. You can really learn alot there.