The City of Holyoke would like to promote an expansion of its innovation-based economy. Building on successful examples from other cities and on already-existing projects in Holyoke, this IdeaBook suggests various strategies, at multiple scales and time-frames, to help create public spaces that foster the social interaction that is critical to innovation. These strategies involve promoting art and creative expression; temporary Òpop-upsÓ; pedestrian- and bike-friendly environments; connections to canals and the Connecticut River; urban agriculture; and urban ecological repair.