Last summer, hip-hop celebrated its fiftieth anniversary, and from its early renegade beginnings to becoming a big fish in the mainstream, many a clever lyric has been turned out by talented rhymers who hit home runs with powerful wordplay. Whether they're poking fun of competitors with scathing cyphers or acknowledging poignant truths about life, the following fifty lyrics stood out for their sharp witticisms, the context they provide to the time they were written, and more. …