Celebrities have been known to exhibit the worst behavi… we mean, grammar. Seriously, just look at their tweets. So Red Balloon, an English school in Brazil, hit upon the idea of having their 8 to 13-year-old students tweet back at celebrities like Paris Hilton, Rihanna and Justin Bieber, to correct their grammatical errors in their tweets. Don’t know about you, but seems a bit passive aggressive. Still, always nice to know that celebrities aren’t above bad grammar.