For reasonably unlimited fun, you can get a random quote from Wikiquote via the Mediawiki API (or a scraper) and show that. This is my scraping attempt in a Ruby one-liner, CC0 licensed, open-uri and Nokogiri gems required:
ruby -r open-uri -r nokogiri -e 'html = URI.open("https://en.wikiquote.org/wiki/Special:Random").read; doc = Nokogiri::HTML html; author = doc.title.split("- Wikiquote").first; print doc.css("li:not(:has(> li))").reject {|e| e.text.start_with? /\d/}.first.text; puts "\n~ #{author}"'
Does not work perfectly, it's a proof of concept but kinda works. Cherry-picked a cool quote it gave me:
The highest morality may prove also to be the highest wisdom when the
half-told story comes to be finished.
The Boer War (1902)
~ Arthur Conan Doyle