YOU MIGHT THINK that Congressional Quarterly, the massive research service, would already have enough on its hands. For 33 years, with graphs, charts, words and pictures, its Weekly Report has furnished a record of how Congaress uses its time - what the committees are doing and who voted for what. It keeps tabs on political races and explains about Revenue Sharing, Hatch Act reform, or whatever else they're talking about up there. It publishes indexes, a yearly Almanac , and a 1000-page hardcover series called Congress and the Nation which synthesizes the Almanacs . In addition, Editorial Research reports, a separate service that C.Q. took over in 1956, puts out studies on social and health issues, economics, foreign affairs - and sometimes art and sports. Its live-in computer can reveal a congressman's lifetime voting record, or trace voting patterns by issues, or spot the location and profession of C.Q.'s "clients": 8000 subscribers including about 400 newspapers, plus libraries, colleges, corporations, banks, government agencies - and members of Congress.

Since it "stumbled into book publishing in the early 1960s," as an old hand says, C.Q.'s paperback list has ranged from Congressional Ethics to Presidential Elections Since 1789. Its $4.75 paperback texts by outside authors are moving into the college textbook market. "We're trying to focus on the area we're best at," says General Manager Paul Massa. "And we have the advantage that from manuscript to finished book is a matter of weeks."

Anyhow, with all this already going on in its new headquarters over by the P Street beach, C.Q. is now about to take to the air. A weekly half-hour television show underwritten by Cities Service, produced by station WCET in Cincinnati and distributed by PBS, will be launched this fall. Written and researched by C.Q. staffers, each show will focus on an issue facing Congress.