Like the great classic Bugs Bunny cartoons, this movie has humor at different levels. I just introduced this to my 10 year old daughter and 11 year old son. Both enjoyed the movie - busting out laughing quite a few times... and my daughter is not much of a sci-fi fan. The movie kept me laughing despite having seen a few times... the adult-level humor (that is, humor that adults will get simply because of greater life experiences, no baudy or R-rated stuff to be found here) keeps the movie equally enjoyable for adults. For example of the adult level humor, the Martian voices are based on characters of different movies/actors. The Martian pilot, Blaznee, has the voice and mannerisms of Jack Nicholson; the scientist, that of Peter Seller's Dr. Strangelove. The special effects are surprisingly good for this film. The lack of top 10 actors actually works in the movie's favor, and the actors/actresses play their part well - in fact I would say the producers picked out actors and their skills for the roles' needs over box-office draw power (an excellent example is Wayne Alexander's "Vern" character). I had to write this review... the kids are playing this for the 3rd time in 4 days over dinner right now. Good for a rainy day or a late night weekend there's-nothing-on-and-I'm-bored movie.

You have to respect this movie. It may be "just a dumb kid's movie" but it's the #1 most frequently requested film title in online movie forums, requested by people who remember the story but can't remember the title. Therefore what follows is a much-needed, detailed plot description, since I haven't been able to find such a description anywhere else on the Internet.
A typical 2-story house is shown in suburbia. 7-year-old Bridget narrates about suspecting something is going on since she and her 11-year-old brother Andrew are getting presents from their parents for no apparent reason. Bridget's present is a stuffed penguin that she immediately names Sweet William. Bridget describes her relatives: Aunt Ruth, a bossy nurse taking care of grandmother, Grams the hugging grandmother who makes dolls out of socks, and her brother Andrew, who's into electronics and is grumpy. Grams accidentally hangs up on the lieutenant-governor, which indicates she's getting in the way while living with the family. The two children eat breakfast while the adults discuss moving Grams to a retirement home. Bridget makes an awful-looking pancake sandwich containing cereal, eggs, bacon, strawberries, and syrup, as Andrew looks on incredulously. The two kids then discuss Grams, and Andrew says bluntly that Grams is being "put out to pasture." Bridget talks with Grams in the attic, has a play tea party with Sweet William in her bedroom, then a living doll unexpectedly pops out of her bedroom closet mirror.
Bridget and the living doll become acquainted. The curly-haired living female doll is named Huggins and lives in Huggaland. Bridget gives Huggins a baseball cap from Andrew's room. Huggins hides under some laundry when Bridget's mother comes by, then the mother throws the laundry into the washing machine with Huggins in it. Bridget rescues Huggins and dries her off with a hair drier. They discuss the problem with Grams getting old and having to move away, Huggins says Bridget could talk to the bookworm in Huggaland about it, since he knows everything. They step through the mirror to visit Huggaland, but one of Bridget's tennis shoes becomes lodged in the mirror.
Rather than walk around with one shoe, Bridget goes without shoes in Huggaland. They immediately meet Hugsy, a curly-haired living boy doll in Huggaland. Huggins gives Hugsy the baseball cap. They also meet Tickles, Bubbles, Impkins, and Tweaker, and all the dolls sing a song while sitting on a bridge. Hugsy takes Bridget and Huggins in his hugwagon to see the bookworm, who lives atop a stack of giant books. The bookworm consults "the old encyclopedia" and finds that old age can be cured by eating the fruit of the "youngberry tree." However, only one such tree exists, and it's in the country of Shrugs, ruled by the mad queen of quartz. The only way to travel to Shrugs is to jump down a deep hole that is located inside a nearby giant book.
Bridget and the two dolls gulp three times, jump down the hole, and tumble out. Soon they walk down a sideways sidewalk, hear the sea of glass breaking, and fall off the sidewalk when the sideways gravity ends. They encounter "the hairy behemoth," which looks like a mastodon, has four tusks, and breathes fire out its trunk. But Hugsy boldly goes over and hugs the behemoth, who thereby turns into a baby elephant whose name is Hodgepodge. Hodgepodge had been under a spell by the queen, and owes Hugsy a favor, so they all ride on Hodgepodge's back to the castle. They enter the castle, are surrounded by troll-like beings, the queen (Queen Admira) comes, and Bridget asks for a few youngberries. The queen refuses, then eats one for herself, and brags about her own youthful good looks while looking in a hand mirror. Hodgepodge faints when the queen says he should be "digested." The queen is upset when Bridget mentions that wicked witches should have warts, so the queen freezes Bridget and orders the three others to be taken to the dungeon. But the queen carelessly leaves the key to the youngberry tree's dome by the lock to the dome-lifting apparatus.
Hodgepodge wakes up in the dungeon and uses his "noodle" (trunk) to pull the jail's door down, thereby freeing himself and the two dolls with him. They find Bridget standing petrified, the dolls hug her, which causes Bridget to be revived. Before they flee, Bridget finds the left-behind key to the youngberry tree dome, lifts the dome off, and they pick some glowing youngberries and put them in a jar. The queen catches them, but the queen's arm is trapped under the descending dome while reaching for the key that Bridget left on the ground. The queen suddenly turns very old since she is deprived of the youth-giving berries, and appears to die. Soon Bridget steps back through the mirror into her bedroom but trips on the bottom of the mirror, spilling the berries onto her floor, and the berries quickly vanish into smoke, one by one. Her mother calls for her and Andrew to say goodbye to Grams, who is leaving for a retirement home. Andrew drops his usual grumpy, standoffish facade and hugs Grams, telling her he loves her and that he doesn't want her to go away. Their father is moved, and decides to keep Grams there after all, and everybody hugs and cries, including Aunt Ruthie, who had been the main person pressuring Grams to move out.
Andrew asks Bridget for his St. Louis Cardinals cap, Bridget starts to explain how she gave it to Huggins of Huggaland, but Andrew doesn't want to listen to what he believes are her fantasy stories, so he turns around to look for it in her bedroom. One of the dolls secretly hands the cap back through the mirror to Bridget, Bridget puts the cap on Andrew's head, Andrew is mystified, and leaves her bedroom without saying anything. Bridget cheerfully waves at the mirror.