Comets are famous (Halley returning every 76 years), awesome (Hale-Bopp), significant (Shoemaker-Levy 9 hitting Jupiter), or duds (Ison). They are mysterious objects from the outer solar system. Beyond Neptune are regions containing icy remnants from the solar system formation. The Kuiper Belt is close and the Oort Cloud is distant. Normally, bodies quietly orbit the sun and if visible at all, are small dots in telescopes. Sometimes they are perturbed; their orbits change and they fly into the inner solar system. These are the comets we see. Currently there are no showy comets, but they can show up at any time.
Comets have a nucleus surrounded by a cloud of gas and dust. There are usually two tails streaming away from the sun. Dust left behind by comets is the material that we see as meteors during meteor showers.
Insperity Observatory Public Night is the first Friday each month: humbleisd.net/observatory.