Isomelody and Isorhythm
An interesting exercise is to take an existing melody (as I did with the Bach cello suite) and map it over another rhythm. You can compose your own or use an existing one. With Be Bach I used the sequence of notes in the Suite and mapped it over a bop rhythm that I composed. After the melody was done I added chord changes. (Someone should write a program that will do this automatically.) Here is the source Bach cello Suite: A more recent video: Using isorhythm in a bass line: