Well, regardless of your religious convictions, the visit at the Baha'i temple on Linden St in Wilmette can be an interesting way to spend a day. The architecture is very nice, they have documentaries available to be seen in the small movie theatre downstairs - and the staff is very nice and knowledgeable, any questions you might hav do not hesitate to ask them. Nobody will try to convert you, they just answer the questions if you have any. And while there, take a moment and take a walk in the gardens around the temple. It can be a nice experience as a Chicago tourist or as a Chicagoan too.