Power Pack (1991)
Credit: Marvel
It's cheating a bit to include this one as it was a series pilot rather than a movie, but I was so surprised when I found out about it I just had to include it.
The original comic run of Power Pack lasted 62 issues in the 1980's. It was about a family of children (Power is actually their family name) who were given superpowers by a dying alien. Whilst the Power Pack dealt with normal childhood issues like school and losing teeth, they also fought a myriad of mainstream Marvel villains. Since the series' cancellation they have cropped up in other titles, as well as having a four-issue mini-series in 2000.
The TV series came after the cancellation of the comic and was envisaged as appealing to younger audiences. It made a few minor to changes to the Pack's powers and had the parents be aware of their children's abilities. The film actually has more in common with The Goonies than comicbook movies. It's not terrible, just a little bland, and wasn't picked up for a full series.
I could actually see this team making a comeback as a Marvel/Disney series aimed squarely at the kids.