Tapping the spacebar displays all selected files in Bridge in Full Screen Mode with a dark grey background. This is a great way to quickly review files without having to open them in Photoshop. Tap escape to return to Bridge.
Command + L (Mac) / Control + L (Win) displays selected images in Slideshow Mode and automatically transitions between images every five seconds using a dissolve. Chose View > Slideshow Options to access additional Display, Slide, and Transition options.