The "safe spot" in Pac Man

All those quarters I wasted in Pac Man, never knowing that there is a square where you can "hide" from the ghosts:

The right side of the T-section beneath the ghost regenerator can be used as a safe spot where the ghosts are unable to find and catch Pac-Man. There are two conditions that must be met to make the safe spot work for Pac-Man. The first is that none of the ghosts must "see" Pac-Man enter the safe spot. If they do, they will follow him in there, and the said spot will not be safe. The other condition is that Pac-Man must be facing north. You don't necessarily need to approach the spot from the south (just to the right of where Pac-Man begins the round). You can enter from the east and quickly change orientation to point north. If you meet both conditions, you can leave Pac-Man in that location for as long as you like and move the joystick when you are ready to resume play. Marathon players of the game often use this trick if they need a break from the game.

Map via The Guardian.  There are many more tips at StrategyWiki.