This film could have been titled “There Will Be Beef.”
I take it as a rule of nature that all American high schools are ruled by a pack of snobs, led by a supremely confident young woman who is blonde, superficial, catty and ripe for public humiliation. This character is followed everywhere by two friends who worship her, and are a little bit shorter. Those schools also contain a group of friends who are not popular and do not think of themselves as pretty, although they are smarter, funnier and altogether more likeable than the catty-pack.
In the classic form of this formula, the reigning blonde dates a hunk who the mousy outcast has a crush on, and everything gets cleared up at the prom when the hunk realizes the mouse is the real beauty, while the evil nature of the popular girl is exposed in a sensationally embarrassing way.
"Sleepover," a lame and labored comedy, doesn't recycle this plot (the blonde gets dumped by her boyfriend) but works more as a series of riffs on the underlying themes. It moves the age group down a few years, so that the girls are all just entering high school. And it lowers the stakes -- instead of competing for the football captain, the rivals enter into a struggle over desirable seating in the school's outdoor lunchroom. Winners get the "popular" table, losers have to sit by the dumpster. That a school would locate a lunch area next to the garbage doesn't say much for its hygiene standards, but never mind.
Julie is the girl we're supposed to like. She's played by Alexa Vega, from "Spy Kids." Stacie (Sara Paxton) is the girl we're supposed to hate. Julie's posse includes Hannah (Mika Boorem), a good friend who is moving to Canada for no better reason, as far as I can tell, than to provide an attribute for a character with no other talking points; and Farrah (the wonderfully named Scout Taylor-Compton), who functions basically as an element useful to the cinematographer in composing groups of characters. Julie decides to have a sleepover, and at the last minute invites poor Yancy (the also wonderfully named Kallie Flynn Childress), who is plump and self-conscious about her weight. Julie's invitation is so condescending it's a form of insult, something that doesn't seem to occur to the grateful Yancy. Julie's mom, the wonderfully named Gabby (Jane Lynch), lays down rules for the sleepover, all of which will be violated by the end of the evening without anything being noticed by her dad Jay (Jeff Garlin), reinforcing the rule that the parents in teenage comedies would remain oblivious if their children moved the Ringling Bros., Barnum & Bailey Circus into their bedrooms.