Do you mean a 3D page flip effect, like a book?
If so, I haven't seen anyone build one yet. It's definitely not a built in effect to the product.
We do support a rotate3D effect, so you can get the basic feel.
1) Create a rectangle
2) Duplicate state
3) In the timelines panel, click page 1 > page 2
4) At the bottom of the timelines panel, add a 'Rotate 3D effect'
5) Specify the rotate to/from parameters to get the desired look. Press the play button on the timelines panel to continuously preview until you get the look you want.
Let me know if this works out for you, and furthermore, I'd love to hear some more detail on how you would envision using effects in Catalyst.