Next Vista for Learning recently announced the launch of their spring video creation contest for students and teachers. Creative Flight is the name of this spring's contest. To enter students and teachers need to create short (90 seconds or less) videos about a concept that one might encounter in elementary, middle, or high school. The video should provide a lesson. The submission deadline is May 3, 2013. You can read the full contest details here.
For some inspiration take a look at the finalist's videos from previous contests. Previous student finalists, previous teacher finalists, and previous student/teacher collaboration finalists. Peter the Great in 90 Seconds was a recent contest winner.