In a medium saucepan, combine water, sugar, and salt. Bring to a boil.
Remove from heat and stir in the flour until the mixture forms a ball.
Let the dough cool for about 10 minutes.
Beat in the eggs one at a time until smooth.
Heat oil in a deep fryer or large pot to 350°F (175°C).
Transfer dough to a piping bag fitted with a star tip.
Pipe 4-6 inch strips of dough into the hot oil.
Fry churros until golden brown, about 2-3 minutes per side.
Remove churros and drain on paper towels.
Roll warm churros in cinnamon sugar before serving.