Modifying “Recent Posts” code

The code for my “Recent Posts” is:

<?php get_archives('postbypost',tiga_recentPostsCnt(),'custom','
<li>','</li>
'); ?>

Now I have another Box called “Games”. Every time I make a post that has “Play ….” in the title I would like my “Games” box to have “….” listed in it.

example: I create a post with the title “Play Chess”. Then let’s say I make a post called “Play Asteroids”

Now I would like my sidebar “Games” box to have

——–
Games
——–
Asteroids
Chess