If you are anywhere near Long Island, NY, you really shouldn't miss the opportunity to visit Brookhaven National Laboratory during one of their Summer Sundays. You get to visit not only the lab in general, but also get to tour the facility that's open for visitors for that day. Typically, the days highlighting the NSLS and RHIC are two of the more popular and tend to have the largest number of visitors, and understandably so.

This is one of the few opportunities one gets to tour a world class science facility and gets to ask questions to scientists working there.

The Relativistic Heavy Ion Collider sounds fun!