A week ago, I noted the degree to which Explorers can chew through content. Explorers explore not only geography but also mechanics, so complex play options with many interactions can keep us going for a long time. For a great example of this, head over to Van Hemlock and see what he has been doing with Guild Wars. With hundreds of skills available, but only one skill bar available at any given time, Guild Wars provides lots of options for builds. He has been taking single skills and making builds around them, then taking them out for test runs. Read some of his posts to see how those are working out.