These formulae provide binary installs of software that, for whatever reason, aren't available as source builds in the primary repository.
brew install homebrew/binary/<formula>
Or brew tap homebrew/binary and then brew install <formula>.
Or install via URL (which will not receive updates):
brew install https://raw.githubusercontent.com/Homebrew/homebrew-binary/master/<formula>.rb
brew help, man brew or check Homebrew's documentation.