Crocheting mats for the homeless using yarn (ahem, “plarn”) made from discarded plastic shopping bags is a brilliant idea. Ruth Werstler, founder of the local volunteer group New Life for Old Bags, admits she didn’t exactly come up with it.

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In late 2009, her father saw a local news report about a group of elderly women in Palatine who were making the mats and e-mailed her a link to the story. Werstler, the “life enrichment coordinator” at a retirement home on the northwest side, initially thought it would be a great way to get her residents involved in something important—not just feeling useful, but being useful. She sent out about 100 e-mails and got an overwhelmingly positive response. “I wrote people back,” Werstler recalls, “and I asked, ‘Are you kidding, or are you serious?’” Apparently they were serious.