I just finished teaching a few classes on Christology. We analyzed the Arian history and the students were surprised to learn that Arianism is still alive in the twenty-first century in the ranks of the Jehovah's Witnesses. The Jehovah's Witnesses (JWs) believe that Christ is a created being who is god-like, but certainly not divine.
If you press the JW, he will tell you that Jesus Christ is the archangel Michael - the chief of the heavenly host, but not consubstantial with the Father. This can easily be refuted by examining the chronology of events as listed in 1 Thess 4:14-18.
The chief error of the JWs is their mistranslation of John 1:1-3. I could go through it all, but Mark Brumley (President of Ignatius Press) has a clear and concise article about how John 1:1-3 confirms the deity of Christ and even unpacks the significance of the Colwell Rule. The Colwell Rule is a rule of Greek grammar that conclusively debunks the JWs false claim that Christ is merely "somewhat divine" and not "God from God". If you're interested in this debate, take a look at Mark Brumley's article: "The God or a god?" over at Catholic Answers.
If you do meet a JW, mention the Colwell rule but also ask him or her to give an account of why Paul prays to Christ if Christ is not God. I once stumped a zealous JW on this point when he tried to "evangelize" me on a rather long flight.