Can I slack and get a PhD?

I am not a genius but I am a good test taker and a very practical person. I went through undergraduate school without studying much (skipping classes, doing homework, reading the books and doing some exercises the day before the test) with a 3.6 GPA in Computer Engineering from a descent school (CWRU). I know I might get angry answers from people saying that it simply cannot be done. I am interested to hear from the people in the other side of the spectrum. Can it be done? Have you done it?