Originally Posted by Ulukia
The closest would be Application Switcher. You can view what is currently running but in order to close them you would have to do so from within that applications themselves. To access Application Switcher, assign to a convenience key from Options > Screen/Keyboard. There might be a hot key but I'm not sure.
You can also press and hold the "alt" key and press the "back" button to bring up the application switcher, you must hold the "alt" and select the application you want with the trackball.