The best thing about smartphones is the nearly limitless number of games available to help alleviate boredom.

The downside is these games are so simple and absorbing that it is easy to forget what you are doing.

The player may find that boredom has been replaced with a single-minded desire to eat brains — I mean, play games.

“Plants vs. Zombie” from PopCap Games is that game. The concept is simple: defend your house from the zombie apocalypse by strategically planting killer plants in your yard to shoot, eat, mow down and blow up the onrushing zombie horde. Players collect sun rays that fall from the sky and use them to earn enough points to plant new plants.

The player can plant sunflowers or yellow mushrooms to generate more sun rays.

There are a multitude of different units to buy and the player gets a new option at each level. This keeps the game interesting because each level is an opportunity to try new combinations of plants and develop new strategies.

The game is mostly played in Adventure mode where players advance through levels sequentially. This also keeps the game interesting because new terrain or new types of zombies are frequently added, so the scenarios never get stale. If the player gets bored with Adventure mode there are lots of mini games, puzzles and short scenarios in the “Other Ways to Play” section. In addition, players unlock more game play options as they progress through the Adventure mode scenarios.

Every so often the player will get a visit from the neighbor, Crazy Dave. Dave is very knowledgeable about zombie killing and lawn care. Why is Crazy Dave so crazy? Nobody knows.

Maybe zombies ripping through his lawn drove him over the edge. Maybe going a little crazy is the only way to stay sane in a crazy world. Whatever the reason, Dave is funny and keeps the mood light. “Plants vs. Zombies” is fun and available on all major smartphone platforms. There is a free version with ads or a paid version and a free sequel, “Plants vs. Zombie’s 2.”