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.