While we're technically not "potty training" with any gusto, Eli has a little potty chair that he likes to sit on from time to time. He calls it "pobby". Without giving too many unsolicited details, I will say that he has used it several times successfully. We are very proud.
He likes his pobby so much that he will occasionally sit down on any other convenient, small round object and call it "pobby". Short stumps in the park, for example. A few days ago, we were in the front yard playing and Eli decided that one of my big flowerpots looked like... you guessed it... pobby. Luckily he is still in diapers so soiling the soil was not an issue.