Percy Jackson of the Percy Jackson and the Olympians series is named after Perseus. Like Perseus, Percy beheads Medusa.

Legend says that Perses, Perseus's son, founded the ancient empire of Persia (source).

The Perseus Arm is an arm of the Milk Way galaxy (source).

The Royal Navy has a number of ships called the HMS Perseus (source).

The Perseus Project is a digital library of humanities resources at Tufts University. It's a great place to find ancient texts.