Effects in iPhoto!
In the Edit mode of iPhoto, there are easy effects that you can apply really quickly. What is really great is that these effects are stackable even if they are not applied yet. To access these effects, you just have to click on "Effects" in the bottom toolbar. Some effects are not just "ON" or "OFF", but are customizable as 1, 2, 3 and more. You just have to use the arrows to remove or adjust the customizable effects.