Really?
Get a DC license....$6.50 for out of towners.
Fish the Tidal Basin for many species (striper, crappie, bass, catfish, snakehead...).
Go to Fletcher's and ask the guys at the shack to see what is biting on the river or canals.
If you like to wade (wet), you can do so at Gravely Point which is technically in VA just across the 14th St Bridge. The in/out flow just south of the ramps gets a lot of attention.
Or....Google up the carp fishing that some guys do off Haines Point, they had an international competition there a few years back.
That's just a few for starters.
Ernie