What a year!
Anyway, the comet was discovered by Malcolm Hartley, and it orbits the Earth once every 6 and a half years - but this time its special, because it's making its closest approach to Earth since its discovery (close = about 11 million miles away).
Look for it towards the East (if you're in the US, I guess), near the constellation Auriga and its really bright star, Capella. It should look like a 'ghostly' green blob (just in time for Halloween). The best time to see it is early in the morning, so when you're stumbling home from a show look up at the sky.