Riders find it hard enough to get a cab in Adams Morgan on Friday and Saturday nights. But a recent boycott of the area by city cab drivers made it even harder. Partiers trying to get home between one and four a.m. last weekend found themselves walking quite a distance or waiting in long lines to grab a cab. Drivers are angry about a recent proposal by DC City Council member Jim Graham to establish a new system requiring drivers to pay a monthly fee in order to operate. That bill was pulled, but cab drivers still say the metered fare system instituted last year needs some modifications.