Red Robin Gourmet Burgers looks like it's going to take an aggressive route in dealing with its activist investors. This afternoon, the Colorado-based company released a letter from its chair, Pattye Moore, taking to task its latest activists, led by Oak Street Capital Management, for saying that the existing board does not have a "sense of urgency" in dealing with its problems. Oak Street made the "sense of urgency" comment largely because Red Robin wanted to wait an entire month, for its regularly scheduled board meeting, to address the group's concerns. She also noted that the company's "Project RED" plan to improve sales and profits was developed well before Oak Street filed its 13D. "We have set for ourselves an aggressive timetable for this strategic task, and while moving fast, have been working to incorporate the views of multiple, key constituencies."