The resources that I shared in the post previous to this one offer games that help students learn and remember the rules of grammar. At the high school level, the following two videos offer fun introductions to grammar lessons.
In Glove and Boots Fix Your Grammar the popular puppets Glove and Boots use fun examples from the web to explain the differences between "its" and "it's," "your" and "you're," and the proper uses of "there," "they're," and "their." Glove and Boots also teach viewers when it is appropriate to use "literally." The video is appropriate for high school audiences.
Weird Al's music video Word Crimes is a parody of Robin Thicke's Blurred Lines in which Weird Al points out some common grammar errors and how to correct those errors. The video is embedded below.
This is meant to be a fun video. Consider your audience and decide for yourself if it is appropriate to show in your classroom.