first post I suggested writing out a solo exploring some concept or idea, and gave you an example solo that I'd written out over the changes of All Of Me. Well, this time my suggestion is even more ambiguous. The exercise is to improvise using a motif or small musical idea, and the point of the exercise is to force you to create new lines and practice a more complete improvisation. Focusing on motifs tends to make you play new things as opposed to following the normal lines and variations you might usually play while soloing.
The motif or musical idea you pick can be anything. The only rule is it needs to be simple and short enough that you can remember it and easily use it. Then, you improvise on it changing and varying it freely as you go along. Rhythmic, melodic, and harmonic variation summarize the possibilities, and you'll probably do all 3 at the same time as you explore a given motif. First, try the exercise without chord changes. Improvise on a motif over one chord, a vamp, a free texture, or some other context that doesn't force you to follow the harmony. Once that becomes comfortable and fun, try the exercise over a simple chord progression, maybe a 12 bar blues.Finally, try the exercise over your favorite tunes.
For my example, I chose to improvise over the chord changes to Donna Lee. Normally, I would be starting and stopping a lot as I try to iron out any kinks during the exercise, but for the sake of the listener I push write on through in this example. The exercise starts out with the following motif:
Ben Plays Motif Based Improv.mp3