Cost: $15; $10 for students and seniors over 62; Free for children 18 and under

Organizer: Global Exchange and Co-Op America

What to expect: Over 300 exhibits will be featured at Navy Pier, including eco-friendly merchandise, how-to workshops, green career info, a Kids Zone and organic food and drink (from Chicago Diner, Cousin's Incredible Vitality, Soul Vegetarian East and others). Plus, there will be more than 150 renowned speakers on hand for panel discussions and presentations.

Why to go: This year's keynote speakers include William Ayers and Bernardine Dohrn, famous for their involvement in the Weather Underground movement of the '60s (and now both local college professors). Other keynoters include Ron Reagan and Alice Waters.

Centerstage Reviewer: Ben Rubenstein