In Approval voting, each voter simply votes for, or "approves," as many of the candidates as desired (without ranking them). As in plurality voting, the votes are counted, and the candidate with the most votes wins. No new voting equipment is needed (except perhaps in rare cases), and the ballots don't even need to be changed. Moreover, the change to the current voting rules is trivial: "vote for one" simply becomes "vote for one or more."
Although trivial to implement, Approval voting goes a long way toward overcoming the "lesser of two evils" problem inherent in our current plurality system, which artificially entrenches our political system into a two-party duopoly without effective competition from other parties. And although Approval voting is much simpler than Instant Runoff Voting (IRV), it is actually more effective according to important technical criteria, with no significant disadvantages compared to IRV.
See for yourself! Vote and compare the results: