Halloween has arrived — and that means people of all ages will soon be donning costumes of all types in their search of sweets. Perhaps it is no surprise that some of this year's most popular costumes draw on pop culture. (See some of this year's celebrity costumes HERE.) There's the mother of eight, Kate Gosselin; the King of Pop, the late Michael Jackson; super-swindler Bernie Madoff; and of course, President Barack Obama. So tonight, we ask: What's the best Halloween costume you've ever seen? We want to know. You can follow "Nightline" anytime on Twitter: http://twitter.com/Nightline.