Now, by definition, Apple's iPhone isn't actually a gaming device.  Software developers have sought to change this, however, by creating some great games that you can play right on your iPhone, without having to add on any extra hardware.  All you need to do is purchase, download, and start using one of the countless gaming apps available from the Apple store.  Here are five games that you may want to grab for your beloved iPhone:

Rock Band

For the musician or music lover in you, Rock Band is definitely a must-have game.  Although it comes at a heftier price ($6.99) than many of the other games out there, you do get what you are paying for.  Not only do you get some great gameplay and fun, but you also get access to a seemingly endless supply of songs that you can purchase to listen to and play along with.

Space Invaders Infinity Gene

For $4.99 you can get Space Invaders Infinity Gene, a remake on the classic game Space Invaders.  This shoot-em up game is new and improved, with a slew of new weapons and a beefed-up interface to provide more fun and excitement to this age-old classic.  In fact, you can even play some of the original stages with the original music.  Some of the other game features include an in-game achievement system, as well as worldwide high score tables.

Bejeweled 2

Bejeweled 2 is a game that you can play for hours without getting bored.  It's a simple puzzle-type game that is highly addictive and very fun.  With a number of game modes and its great price point ($2.99), Bejeweled 2 is definitely a game worth looking into.  If you are a puzzle gamer who enjoys sudden-death frenzies or competing for scoring titles, then this may just be the game for you.

Real Racing

Real Racing is a racing simulation game that has a lot to offer.  With its impressive graphics, great controls, and wide selection of cars, tracks, and game modes, Real Racing is definitely one of the best racing games you can find for the iPhone.  With a $4.99 price tag, this game is a steal, especially if you can find other friends to play with through local or online networking.

Shredder Chess

There is a wide variety of chess games out there for the iPhone, but one of the best is Shredder Chess, which costs $7.99.  Although the game doesn't feature amazing graphics, it makes up with great functionality.  Shredder Chess offers challenging and adjustable AI, play ratings, game analysis, chess coach, save and load options, and the ability to enter and analyze any move or position you like.

These are just some of the games that are worth having in your iPhone.  iPhone users never have to feel lonely or bored with these exciting games to keep them company.