Aware is a menubar app for OSX and macOS that displays how long you've been actively using your computer.
View in Mac App Store or download the latest release from GitHub.
Requires Xcode 7.2.
$ git clone https://github.com/josh/Aware
$ cd Aware/
$ open Aware.xcodeproj/Copyright © 2016 Joshua Peek, Patrick Marsceill. All rights reserved.