Southern evenings, especially in the transition from day to dusk to night, are filled with sound; cicadas and day-singing crickets give way to evening-singing crickets, katydids, and tree frogs. I love the nocturnal symphony.
Distinguishing between them takes some study. I've been working on it for awhile (although perhaps not diligently enough!) Lang Elliot's The Sounds of Insects is loaded on the main iPod, but I need to put it on the small one that I take walking or when I'm in the garden. It's not the first thing I'd think about listening to, though, I'm afraid. There's definitely an instructive aspect to trying to listen to sequences of insect calls that isn't that appealing, but maybe it's just a new language to learn.
I just had to look up whether it was cicadas or katydids that called during the day (they have similar loud raspy calls), but I'm beginning to be able to hear the differences between tree frogs and the different species of crickets (hmm). There are so many things to have fun learning about, sometimes I think I get almost distracted with the possibilities.