This is a site for teacher-created resources to be purchased and downloaded  by other teachers.  Prices are reasonable (e.g. $4.00 for a conversation activity on 'annoying things' that consists of an editable powerpoint slide deck, teacher notes and 2 student worksheets for reproducing.  Lessons and materials are available for K-12 as well as for adults.  This link will take you directly to the adult ESL section  secondary level materials as many would be suitable for adult classes as well.