IdeaPaint, Cambridge, Mass. Want to spur innovation? Turn every wall, no matter the surface, into a whiteboard. Three recent Babson College graduates created a paint that dries to create a surface that does just that, and any dry-erase marker wipes it completely clean. The paint sells for $3.50 to $4.00 per square foot of coating. After closing a $5 million venture round in December 2009 (following a $5 million round in November 2008), the founders plan to have it in at least one big-box store in early 2010.