Dragonball Evolution is adapted from the manga created by Akira Toriyama; the work was also turned into a Japanese anime series that played all over the world. It tells the story of an alien sent to destroy Earth, who has a change of heart and decides to join the humans in their fight against various aliens and bad guys.
This movie was retarded. Every facet of this movie was crap. Granted I'm not a fanboy and never watched anything to do with Dragonball, but I couldn't imagine fanboys enjoying this movie too much either. Its yet another cartoon/video game adaption that might have been acceptable if it were the late 80s/early 90s, but is a total waste in this day and age in terms of effects and what not. This is straight up garbage that is meant to take advantage of the kids and fanboys who love Dragonball.
I wouldn't recommend anyone wasting their time with this. Its just a blatant waste of time.