HOBOKEN — A lot is going on in Hoboken, but what could be more important than an orange blimp passing over town, advertising the Conan O’Brien Show on TBS? It floated over the mile-square city Thursday night. The blimp actually sends out Tweets so you can follow it. Conan’s website at teamcoco.com says, “Check into it on Foursquare if you see the gassy behemoth near you.” So remember, kids, if you study hard and go to Harvard, someday you might have your own glowing dirigible too.