Tim Grundmann, the zany who regularly hatches musicals for the New Playwrights' Theatre, has pulled a switch: his latest work consists of four tuneless sketches about men who once made music-- Beethoven, Bach, Mozart and Brahms. He calls this engaging exercise in madness "The Lives of the Great Composers," and it is about as faithful to history as Henry VIII was to his diet.

As Grundmann sees it, for example, Beethoven (a dashing Scott Sedar) is Germany's most successful designer of dickeys and turtlenecks, until the bottom falls out of the fashion market. Dispirited, he turns for consolation to his live-in doxy (Tanis Roach). "There's a lot a man of your talent can do," she tells him. "Have you ever considered writing symphonies?" He wants to know what this "big brown box" is. She tells him it's a piano she's just purchased. "Is it hot?" he asks, warily, before sitting down and picking out, unaided, "Chopsticks." The symphonies come shortly thereafter.

Bach turns up in an "I Love Lucy" pastiche entitled "I Love Anna." Nutty Anna Magdalena (Bari Biern) has inadvertently scissored ber hubby's compositions to make "paper panties" for the lamb chops, and his latest Mass got carted off with the morning garbage. Now Handel is coming for dinner! What to do? Anna has a brainstorm. Turning to her neighbors, Helga and Fritzi Kurtz, she babbles, "We are going to write Johann a new Mass!"

In a stand-up Las Vegas monologue, Mozart (a wonderfully smarmy Steven Le Blanc) recounts his triumphs at the court of Louis XVI and Marie Antoinette. ("I was having a ball, just going like gangbusters on that sonata!") As for Brahms, well, things get a little complicated since a movie executive and his yes-man are trying to squeeze that composer's life into the traditional movie genres. Finally, they hit upon the idea of a musical courtroom drama. ("Would you kindly tell the court, in song, what you were doing the day of the murder.")

This is not quite vintage Grundmann. The sketches go up and down in quality and, as a general rule, they're too long to sustain the madness in the initial conceit. Nor is Grundmann always above the obvious. By the same token, he can be gloriously inventive, and it's never too long before he has pounced on some crack-brained notion or other. (His vision of Germanic footwear -- "Bavarian sod-busters" and "strasse-strollers"--rivals the tureen of "slug soup" on Bach's dinner table.) If his sensibility doesn't always shine through consistently this time, Grundmann can still lay claim to the most unique mind working in Washington theater today.

He is very well-served by the appealing cast of five that jumps in and out of a couple dozen roles, as if they were jumping in and out of a brisk shower. Roach has become a particularly adept practitioner of Grundmann-mania, but the others are operating on the same ultrasonic wavelengths. The sets and costumes go for baroque, and short of bringing out the pruning shears, Ken Bloom's chipper staging gives the sketches every possible break.

It makes for an evening more lunatic than not. Where else but in "The Lives of the Great Composers" will you learn that Handel, in his desire to pep up his bank account, dashed off jingles for "Lice-Away" wig defoliant?The show goes on through March 28.