Perseus is the hero who saved Andromeda from the sea monster - what a swell guy! He was able to do this because he cut off the head of Medusa, that lady with all the snakes for her hair. Looking at Medusa would turn you to stone, but Perseus was able to do it with some cleverness and skill. He then turned the sea serpent that was going to eat Andromeda to stone and carried her to safety, where they lived happily ever after.
The head of Medusa is represented by the stars near Algol, and Algol in particular is worth noting. This is an eclipsing binary star, one that changes it brightness in a very periodic manner. The neat thing about Algol is that the change in brightness is visible to the naked eye - ancient astronomers knew that something was funny with Algol since, unlike all other stars, changed brightness.
The constellation of Perseus is full of a bunch of material from the Milky Way since the plane of the Milky Way passes right through it, so if you look at Perseus with a pair of binoculars, you would see some fuzzy things in the area.