One way to make a draw in chess is by perpetual check: if one can get to check the king of the opponent forever, the game is a draw. For instance, look to the following position:
White to move. How can white make a draw?
It does not look too good for white: black can mate him in one move, e.g., by moving his queen to a3. However, he can force a draw by perpetual check: he can continue to give check, and the game is a draw.
Note that to have perpetual check, it is necessary that the same positions appear after a while; just giving `a lot of' checks after another isn't sufficient to have perpetual check.
The animated gif has been made with help of AniMagic. WWW page written and diagrams drawn by Hans Bodlaender.
WWW page created: March 10, 1997.