CiviCRM has demo installs where you can "click around" and try things out:

• Drupal at http://demo.civicrm.org/drupal/
• Joomla at http://demo.civicrm.org/joomla/

Login as demo with password demo.

If you get an "access denied" message, clear your cookies and cache and then login, or try a different browser.

In addition, the sandbox at http://sandbox.devel.civicrm.org/ allows community members and developers to explore new features in upcoming (Alpha) releases and help identify bugs in the release prior to the Beta launch.