“Having fun isn’t hard, when you’ve got a library card!” Come catch Arthur the aardvark roaming the streets of Copley Square this weekend, as GBH partners in its fourth year and first time as presenting partner with the Boston Book Festival. This year, over 200 moderators and authors are meeting in the city for literary discussions that are free to the public. GBH personalities are moderating eight sessions with authors and visitors can stop by the GBH tent outside of the Boston Public Library to meet GBH News reporters. The public will be able to meet them, as well as snag some GBH swag, from stickers to tote bags.