There are literally thousands of themes.

1)  Once you login to WordPress, click "Appearance" -> "Themes".
2)  Then there is are two tabs at the top. "Manage" and "Install Themes".
3)  Click the "Install Themes" tab and you can search by color, etc. From there you can choose a theme and activate it.

:::  Just in case you want to download a different theme from WordPress.org follow these steps:

1) To find additional themes, look on the WordPress website theme section and, after making your selection, click "Download for your Self Hosted WordPress site". Download the files to your local PC or Mac.
2) Upload the theme's folder to your wp-content > themes folder using any FTP client.

- See more at: http://theme.wordpress.com/ Keep in mind that some of the themes from WordPress.org are not free. The themes that you can find by searching in WordPress on your web hosting account with our company, however, are free.