Rhythm is the most important part of sight reading. If you have correct rhythm but incorrect pitch, at least you will be in the correct place. If you play the correct notes but the wrong rhythm you will quickly become lost.
To create a random set of rhythm:
Once you have mastered rhythm, move on to melodies. Choose from four different clefs, multiple time signatures, note ranges and intervals. Change the tempo and even add a metronome to the background.
Want to practice just triplets or sixteenth notes? Custom levels are available for both rhythm and melody practice and allow you to practice only the rhythms you want to work on.
Or perhaps you want to work on sight singing? Set the custom level to quarter notes and adjust the interval setting to change the difficulty.