In "Bowfinger," an aspiring producer-director on the wrong side of 49 has come to the end of Sunset Boulevard. But unlike the legendary Norma Desmond in the original "Sunset Boulevard," he has neither movie classics to savor nor champagne magnums to dull his pain. Bobby Bowfinger (Steve Martin) is a hapless dreamer who can't pay his phone bill, waters down the wine and has yet to make it big time. Has-been would be a step up for this never-was.

"Bowfinger," a sketchy, sometimes explosively funny romp pairing Martin and Eddie Murphy, follows Bobby's last, mad lurch for the stars. Inspired by his latest birthday ("They can smell 50," says Bobby of the youth-obsessed industry's power brokers), Bobby enlists a motley crew of fellow bottom-feeders in a daring scheme.

With their unwitting help, he figures he can trick America's favorite action hero, Kit Ramsey (Murphy), into headlining his new project: "Chubby Rain," a loopy sci-fi adventure about an alien invasion, penned by his cherubic Iranian accountant (Adam Alexi-Malle). As Kit attempts to go about his daily life, actors (Heather Graham, Christine Baranski and Kohl Sudduth) approach him in the streets and deliver cryptic lines about aliens falling to earth in raindrops.

Meanwhile Bobby and his crew of illegal Mexican immigrants record Kit's reactions via hidden camera and sound equipment. Although Bobby picked them up as they ran across the border, the Mexicans are soon sporting Ray-Bans, perusing Cahiers du Cinema and doubtless saving up for their cell phones. This could take some time, because they are literally working for pennies on a no-budget film.

However, "Chubby Rain" is coming together quite nicely and there are only a few more scenes to shoot when disaster strikes. Kit goes into seclusion at the Celebrity Relaxation Center of Mind Head, a pseudo-religious group whose members ascend levels and wear pyramid-shaped hats. Kit, overwhelmed by paranoia, seeks reassurance from his New Age guru (Terence Stamp), who previously helped him overcome his fear of aliens. And other kinks.

As luck would have it, Bobby discovers the arrogant actor's geeky look-alike in Jiff (also Murphy). Jiff is as bashful as Kit is brash and as cooperative as the sulky star is demanding. In one hilarious sequence, Jiff runs across an eight-lane freeway at rush hour. Bobby has assured the trusting soul that every car is manned by a trained stunt driver who knows exactly what to expect.

Murphy, at his most lovably dull-witted as Jiff, just as expertly pillories pampered, overpriced, insecure movie stars. In Kit's case, there's an added comedic element. He's convinced of an industry-wide conspiracy to give white action stars the best catch phrases, as he makes clear to his agent. "Where's my 'Hasta la vista, baby'? Where's my 'Show me the money'? If Arnold Schwarzen-whitey gets to say 'Hasta la vista, baby,' you better make sure that Kit Ramsey has something equally well written."

Martin, whose character seldom interacts with his fellows in any real way, portrays Bobby as though he's been burned out from the years of desperation. Martin's main contribution is his screenplay, which offers clever dialogue and plenty of comic calamities. Alas, the movie lacks emotional depth and intellectual sincerity.

It's best as a send-up of Hollywood humbug, but its barbs are rather blunt. "Bowfinger" is seldom up to the droll savagery of "The Player" or as slyly outrageous as "Get Shorty." Bobby Bowfinger may be an unsavory character, but he's just a pussycat in the man-eating land of Leo the lion.

Bowfinger (91 minutes, at area theaters) is rated PG-13 for language and sexual insinuation.

CAPTION: Bobby Bowfinger (Steve Martin, far right) and his motley crew, going for a long shot.

CAPTION: Daisy (Heather Graham) and Jiff (Eddie Murphy) are part of Bowfinger's bizarre scheme to make a film called "Chubby Rain."

CAPTION: Eddie Murphy, who plays two roles, and Steve Martin, who plays the title role and wrote the screenplay, let the tomfoolery fly in "Bowfinger."