Though their day jobs often involve a plethora of costumes and hours in a makeup chair, many of our favorite sci-fi stars still enjoy stepping out in costume for a good time on All Hallow's Eve. So for the 31st—and final—of our 31 Days of Halloween features of 2012, we take a peek at the Halloween duds of nearly 20 sci-fi celebs.
If you squint just right, How I Met Your Mother can be seen as a sci-fi show. Its stars certainly have sci-fi cred thanks to Neil Patrick Harris (the Dr. Horrible of Dr. Horrible's Sing-Along Blog) and Alyson Hannigan (Buffy the Vampire Slayer's Willow Rosenberg). And the series IS being told from the year 2030 after all.