Now a days smartphone and tablets provides you a slider for unlocking your device. You might have seen this feature in iPhone, Nokia N-Series, Sony Xperia and other popular brands; their smartphone automatically locks and to unlock it you need sliding your finger from left to right on the screen. Now you can use same kind of slider in your WordPress site for fighting spams in comments.
A cool AJAX login widget with SSL support is available for free download in WordPress plugin repository. Best for website owners who wants to avoid redirect to WP login page from users.