I'm going to have to agree that even for a drummer like me, a two-chord vamp is boring! Having a nice set of chord changes to pass through makes even a jam worthwhile.
I would suggest taking the changes of a standard or even pop song then use that as a basis - you can even improvise a new "head" and voila! new composition.
The only time a one or two chord vamp can become interesting is if a soloist knows how to build up tension in the solo - start off slow and exploratory and build up to an intense burn, coltrane style. The rhythm section's job is to nudge the soloist slowly towards the climax of the solo (yes that is a sexual reference, but good jazz is like good sex). Then - after peaking, the soloist should back off and let the next soloist come in. Nothing worse then the guy in the jam who keeps on hogging the solo spotlight, going nowhere with his improvisation. Then the jam become BO-RING even to the other players. This happens a lot with players who aren't used to the art of the jam.
For a good education, watch Tots Tolentino when he plays and builds up his solo ... then backs off after he peaks, and passes the baton to the next guy, or takes you back to the head.
