I don't have a specific event for you to try during your weekend nature excursions -- just a lovely Metro Park on the West Side. They call it Prairie Oaks, and that's appropriate: Lots of verdant meadows and tall forests are present.
Right now, along the gravel paths that wind between both habitats, you'll see chickory, Queen Anne's lace and other summer wildflowers bursting from tall native grasses. From the Whispering Oaks Picnic Area, loop the north and south sections of the Coneflower Trail. After that, take the Darby Creek Greenway Trail north to the River Rock Trail to see the Darby Bend Lakes.
This hike should give you a quick intro to the various habitats on site. If you're dating, bring that person along. You'll be glad you did.
[Prairie Oaks map]