Aura is an ambient sound generator which combines soothing forest sounds to create a comfortable, relaxed atmosphere.
Launch the program, it adds an icon to your system tray, and immediately starts playing its samples: woodpeckers, cuckoos, rooks, crows, water, wind noise and more.
These samples are all played randomly, so there's no pattern to distract you (this sample plays, and it's always immediately followed by another). Just leave it running in the background and it could probably play all day without you getting bored.
Although if this does get too much at any point, you can turn it off by left-clicking the system tray icon or - once you've set it up - using a hotkey.
Aura also offers plenty of ways to configure and customise its soundscapes. You're able to enable or disable each sound type by checking boxes, switch between "Forest in daytime" and "Forest at nighttime" modes for a different feel (nighttime has a bonfire and owls, for instance), add custom sound samples of your own, tweak the volume, and more.
All this is easy enough to launch and stop whenever you like, but there are some automation functions if you need them, including an option to use Aura's sounds as a gentle alarm clock.
Aura has plenty of great samples, and is very configurable. The interface is quirky in places and some actions are more awkward than we expected, but overall it's still a very likeable program.