Ruby has many uses for the % character. One of the more obscure uses is as a notion for custom delimited strings. Use the percent notation with a non-alphanumeric character to surround a string.

> %=Jurassic Park=
=> "Jurassic Park"
> % Ghostbusters 
=> "Ghostbusters"

It even works with balanced characters

> %(The Goonies)
=> "The Goonies"

This is useful for defining a string that has both types of quotes

> %[That'll be the "day"]
=> "That'll be the \"day\""

It’s also useful for creating horribly obfuscated code

> %=what===%?what?
=> true

h/t Josh Davey