I have the same problem (though usually caused by me). We recently purchased a house that has new plumbing & toilets, but perhaps the water conserving kind. Ironically, I have to flush 2-3 times every time it plugs up so I doubt we're conserving much water. This probably happens at least 50% of the time (when going #2) so its a real hassle, not to mention embarassing for guests. Would also appreciate any help.
W.D.