When Lexington native Rachel Dratch was a member of the Second City comedy troupe in Chicago, she conceived and performed a sketch about a mother and daughter shopping at the Burlington Mall.

Undeterred, Dratch developed a variation on that Hub-centric sketch when she became a featured player on NBC's "Saturday Night Live" this season. This time, audiences have responded enthusiastically to the character of Denise in the "Sully and Denise" sketches, and have also lapped up Dratch's mercilessly funny Calista Flockhart imitation.

Tomorrow night, Dratch may perform a "Sully and Denise" sketch with someone else who knows his way around a Boston accent: Ben Affleck. The Cambridge-bred actor is