Is there any way to play PC games on Mac computers

If you want to play games on the Mac, there is a wide selection of games you can buy and play on the Mac. Steam and several games are available through it for the Mac.
There is also a software called Wine to run Windows software directly on Macs. It is a bit difficult to use on macs, so its better to use a Mac program that uses Wine. Crossover is a popular choice, though it is not free. Some free choices that use Wine, is Wineskin and WineBottler. Wineskin was designed originally with games in mind and usually gives a much better gaming experience for fullscreen gaming. WineBottler uses Apples X11.app which has several limitations, but can be upgraded some by manually installing XQuartz. Wineskin has everything built in that is needed.

You can do that, or use Apple Bootcamp, which will let you split up your hard drive on your mac and install Windows. This will let you boot into either Windows, or Mac OS X (not both at the same time), and then when you are in Windows, your mac is basically like a Windows computer.

There are also Virtual machines like VMWare Fusion and Parallels that let you run a virtual computer on top of Mac OS X and run Windows inside of that. It uses Wine technology for the graphics, so it has some potential, but with the overhead of running a whole virtual machine and a real licensed copy of Windows, it's gaming performance is usually always the lowest of any of these choices.