Annoying exes and telemarketers never seem to get the message when you're ignoring them. Instead of answering their call and telling them off, use Blacklist. It will hang up on any number you want or send it straight to voice mail. You can even modify it to only accept calls at a certain hour.
This app doesn't block calls in the traditional sense. Instead, when active, it pushes any of the calls on your list straight to voice mail or hangs up on them. You can password protect the app, but to do so you have to use the app's menu, which is not too user-friendly. Not only are the icons small enough to set off accidental presses, but some of the menus hide other apps from the developer. The app's main menu includes some of these ads, too. However, for the amount of features in a free app, the ads could be much worse. Blacklist only blocks calls when it's loaded. To schedule blocking, you need to pay about $3 to unlock the full version. That may be your best bet if you're looking to avoid callers altogether. It's less than most carriers ask to block numbers, anyway.
Looking to avoid certain callers for good on your Android phone? Blacklist is the right app to download. In spite of some weird hiccups and annoying ads, the free version of this app gives you most of the call-blocking features you want. If you go for the pro version, you're unlocking one of the best call management apps around.