The term Rhythm Changes refers to a progression based on the George Gershwin song I Got Rhythm. Over the years there have been many new melodies (or heads in Jazz terms) written on this progression and it is still routinely used by musicians jamming together or auditioning a new band member.
The following example shows the basic progression in the key of B flat. The ideal tempo is quite fast, so practice the progression with a metronome first. Start out slowly and then increase the tempo once you can play it perfectly.
There are several new chords used in this song. The chord fingerings are shown next.
Gm7
Cm7
F7
Ebm
Eb
Bb7
Rhythm Pattern