Yep, this absolutely “counts” as an extracurricular activity, and college officials are likely to be far more interested in your political videos than they are in seeing the same old stuff that crops up on application after application (debate, band, yearbook …).
But make sure that you adequately explain what you’ve accomplished. The Common App only gives you 150 characters, so you may want to send a separate “annotated” activities list that includes a paragraph or so to describe those undertakings that aren’t immediately obvious. You could even use your essay or the “Additional Information” section of your applications to provide details. And, of course, one picture is worth 1,000 words, so be sure to include a link to your videos. While some busy admission folks won’t have the time or interest to follow it, others may be intrigued (and, hopefully, enthused!).