As far as I know there are three. Possibly four.
1. The Infallibility of the Pope
2. The Immaculate Conception of Mary
3. The Assumption of Mary
4. The impossibility of ordaining women
The first one is infallible because it was a decree of an Ecumenical Council (Vatican I). The decrees of the Ecumenical Councils (Nicaea, Trent, Vatican I, etc...) are also infallible.
To Soothing Dave, if #4 is not a teaching of the extraordinary Magisterium, it certainly is one of the ordinary Magisterium and, because that is the case, the impossiblity of ordaining women is Truth.
Liberalism, and it's brother Modernism, is a sin. Can I get a witness from the congregation?
Pray for John Paul II
Now we extraordinary Magisterium and an ordinary Magisterium. I await further categories.