I wanted a simple program that showed when target spacecraft would be above the horizon. I remembered a picture of an old program that Rob Bruninga posted on AMSAT-BB. I could not find that picture, but I built something similar. It's a simple program that plots the elevation of upcoming satellite passes and then updates it in real time.
There are quite a few display options, including a dark or light theme based on Ethan Schoonover's Solarized color scheme. You can also toggle it to show if the spacecraft are in eclipse:
The installation is simple. You need Java 1.8 or later installed. On Windows put the program in any directory you like and just double click the exe to run it. On Linux or Mac double click the KlaTrack bash script to launch it. Ask me if you need help.