OOPS! I just changed my tar folder and all sub contents to CHMOD 0777
 

How do I change it back? They were all arcade games in there.

Easiest way is just use the change attributes feature of your FTP client.

What does that mean? How do I do it?

Use the FTP client program to browse to the relevant folder on your website.
Most ftp clients will let you right click on a folder or file and let you do something like CHMOD or CHANGE ATTRIBUTES.
You then choose the attributes value you want, (eg 755) or it may have a series of selection boxes where you tick what you want.

Then click ok and its done.