I have been interested in using Prezi for awhile. I started one awhile back when I had about a 1 hour deadline to create a presentation and realized it was more complicated than I could do in the time period.
At yesterdays #coffeecue one attendee was working on a presentation and inadvertently had the canvas rotated 45 degrees. After a Google search we were able to determine that she had accidentally hit the 3 key.
Press the 3 key and the canvas will rotate to the left.
Press the 4 key and the canvas will rotate to the right.
This does not change your presentation at all, just your view of the canvas while you are editing.
FYI: For those of you whose students have iPads there is a free iPad app to allow for viewing of Prezi presentations.