Celebrities took to social media to pay tribute to Harold Ramis:  https://twitter.com/BillyCrystal/statuses/438009264674598912 https://twitter.com/SethMacFarlane/statuses/438009013616132096 https://twitter.com/Jon_Favreau/statuses/438006401223249920 https://twitter.com/ZacharyLevi/statuses/438016299428769792 https://twitter.com/pattonoswalt/statuses/438019454341894144 https://twitter.com/jimmykimmel/statuses/438017262985826304 https://twitter.com/RickMoranis53/status/438017798707871744 https://twitter.com/RealRonHoward/status/438039535495426050 https://twitter.com/kingsthings/status/438055906681446400 https://twitter.com/zachbraff/statuses/438014075130216449 https://twitter.com/nerdist/status/438005322318233600 https://twitter.com/jason_omara/status/438018796088221696