Day-O [Not Rated (but family friendly): Made for TV] 
Overall movie: ***
EJW content: Cute as the dickens and possibly the closest he's been to playing himself, adding up to great fun but not Oscar-caliber acting (although even here there are moments). A full co-starring role.
Note on availability: Day-O is the Holy Grail of Elijah Wood movies. After several years of trying to track down a copy, I finally have available a taped-from-TV DVD dubbed in German. This was made possible through the international collaboration of fellow Faculty members, as was the English synopsis I've made much use of. I still haven't found a commercial source for the movie, or a way to get it in its original English. So, while this is something of a milestone, the search isn't over. Any leads are still greatly appreciated! (Because of this limitation, Day-O is the only movie on this site for which the screencaps are not from a legally purchased source. But, believe me, if I can find a source from which to legally purchase it, I'll be only too glad to do so!)
This is another early-1990's made-for-TV movie, which means both money and time for production were short. But I think it fares better than Child in the Night, because it seems to recognize the limitations of the genre and doesn't try to be anything other than it is. It's a comedy, but not a slap-stick or laugh-out-loud one, with just enough heartwarming "awww" moments added. The story is predictable, and the main antagonist sees the light a little more easily than seems plausible, but this isn't meant to be high drama. All the characters, including the main ones, are broadly drawn, and the minor ones are basically "types" who fill their necessary slots in the story. Even so, I think we get some insight into Grace (Delta Burke), and the least stereotypical character is probably her husband, Ben (Charles Shaughnessy), who's not as easily labeled as most of the characters are.
Another drawback of the genre, as mentioned in the review of Child in the Night, is that these movies tended to get dated very quickly. Day-O fares better here, too, because the issues are more universally human and also, I think, because of the flashback scenes, which keep us from getting too rooted in 1992. But the fashions and other details (an umbrella baby stroller!) can't help but evoke the time.
Elijah plays Grace's imaginary friend, Day-O, whom we first meet in flashbacks from her childhood 30 years earlier. He turns up again at a time when her life seems to be going out of control and she's anything but happy. Of course (and it is quite "of course"--that is, predictable), he reminds her of all the important things that a person in a movie like this needs to remember, and helps her gain confidence in herself. The comedy comes from the reactions of people who can't see him (every adult but Grace), and from his own reactions to modern life after being out of circulation for 30 years.
Day-O, besides being imaginary, is a happy, confident kid, who's all boy but wise beyond his years. Sound familiar? If there's any movie in which the character inhabits Elijah instead of the other way around, this could be it. Not that that's a bad thing. It's fun watching him be himself, and catching little flashes of who he'll be in the future. It was the experience of making this movie that led Delta Burke to predict that Elijah was going to "own Hollywood" someday. Happily, owning Hollywood doesn't seem to be something Elijah particularly cares about, but her point is well taken. "Someday that kid will be a heartbreaker," is another prediction that could easily have been made from this movie (and probably was, more than once).
Sadly, I can't point you to any source for buying this movie.
But hope endures.