Flash version of CS

No need to explain further, right? It's just CS directly in the browser! However, it seems like you need to install the Shockwave plugin first, which is essentially Flash version 10 or higher. You can safely install this, but during the process, it will prompt you to install the Yahoo Toolbar or other things. That’s up to your own needs; I only installed Shockwave and personally tried it out (got headshot, damn, don't know who did it).