Apple Keynote 2 - Manual (Page 140)

140 Appendix A Presentation Keyboard Shortcuts
For a complete list of keyboard shortcuts, choose Help > Keynote Keyboard Shortcuts.
Scroll notes down D
Other
Hide presentation and show last application
used H
Pause presentation F (to resume, press any key)
Pause presentation and show black screen B (to resume, press any key)
Show or hide the pointer C
Show or hide the Presenter Keyboard
Shortcuts window Question mark (?), slash (/), Help
To perform this action Press these keys (or type)
*To use these keys without having to press Shift, turn on Caps Lock.