VEGAS VACATION — ★ ★ — Chevy Chase, Beverly D'Angelo, Randy Quaid, Wayne Newton, Ethan Embry, Marisol Nichols, Wallace Shawn.; rated PG (profanity, vulgarity, bikini babes)

Chevy Chase and Beverly D'Angelo (oh, yeah, and Randy Quaid) are back for their fourth "Vacation" movie, as Clark and Ellen Griswold, this time having a family vacation in Las Vegas.

And it was probably inevitable. Where else can you go and get this many commercial endorsements, short of setting the entire film in Disney World? (What's next, a Caribbean cruise with Kathy Lee Gifford? Maybe a "Vacation" television sitcom - each week Chase and D'Angelo head for a different getaway.)

To review, the Chicago-based Griswolds' first trek was a westward road trip in "National Lampoon's Vacation" (1983). Then came "National Lampoon's European Vacation" (1985), and just as inevitably, the homebound "National Lampoon's Christmas Vacation" (1989).

Where does this one land? "European Vacation" is still the worst, but "Vegas" is a close second. (None of the sequels has managed to reach the inspired heights of lunacy - and bad taste - reached by the original, however.)

As for this one, it's not really awful - it's just dull.

The plot - merely an excuse for a string of gaudy Vegas comedy skits, of course - has Clark Griswold getting a bonus at work and planning a vacation in Las Vegas, which he has read is now family-oriented. In his mind, he sees this as a bonding family trip. But, as you might guess, that's not how things play out.

Once there, Clark is bitten by the gambling bug and eventually blows the family's entire $22,000 savings on blackjack.

In his absence, his adolescent kids Rusty and Audrey (now played, respectively, by Ethan Embry and Marisol Nichols) head out on their own. Rusty gets a fake ID, wins at craps and makes a bunch of new, questionable friends. Audrey hangs out with her less conservative cousin, parties with a trio of Beatles impersonators and winds up dancing in a cage at a disco.

Mom, a Wayne Newton fan, finds herself drawn into a questionable liaison with the big guy himself. (Newton is certainly a good sport, spoofing his own image as superficial and mildly sleazy - but does he realize what a creepy geek he looks like?)

The Griswolds also link up with weird cousin Eddie (Quaid), his long-suffering wife Catherine (Miriam Flynn) and their strange children (love that teenage son with so much pierced jewelry that his mouth is stapled shut; he looks more like the son of Hannibal Lecter).

There are some amusing bits of business, but most of the way this is pretty half-hearted, including Chase's slapstick, as he wrestles a potted plant or trips over a bicycle.

D'Angelo gets a few moments to shine and Wallace Shawn has some funny stuff as a cocky blackjack dealer. But Quaid's shtick grows old fast . . . despite a few clever one-liners.

This is the first "Vacation" movie to get a PG (the first was R and the others were PG-13). That may explain the absence of "National Lampoon" from the title. It's not raunchy enough.

"Vegas Vacation" is rated PG for profanity, a barrage of vulgar gags, some nude statues and poolside bikini babes (female torsos in closeup, of course).