Call Blocker/Privacy Manager

Hey r/iphone, recent convert here (I came from the Samsung Droid Charge 4G... Yes, I gave up 4G speed for an iPhone). On my previous droid OS phones I had an app called "Call Control - Call Blocker." It does exactly what the name of the app says... It blocks calls. You create a "black list" and the phone will, depending on your settings in the options, send the call directly to voice mail, pick up and hang up or just silence the ringer. Now, I've been looking through the Apple App Store and I haven't found anything comparable. Am I missing something? Is there an app I can use to block certain numbers? I've had the same phone number for years and even though I'm on the Do Not Call registry, I get calls from political surveys, random sales and who knows what else.

tl;dr Is there an app I can download to block calls from specific numbers?