Comment only access in Google Docs. http://goo.gl/8R80j you can now share a worksheet, book review, or any Google Doc with students and allow them to freely add comments, but not change the content.
Page Level Access in Google Sites. http://goo.gl/KthNR You can now set permissions on individual pages in Google sites. This allows you to turn access on or off for specific individuals. You can share on your website that only a specific class or group of students can access.
Offline access for mail, calendar and docs: I have used Google Apps for over a year now, and have not really felt cheated by not having this option availbe to me, but it's a nice option to have avaialbe especially if you are headed out on a vacation and do not have access to the internet. It's also a nice option to have available if you are using a Chomebook. http://www.google.com/chromebook/ (I love these things.) Make sure you are using the Chrome Web browser (Shame on you if you are not.).
For more information:
Gmail offline: http://www.google.com/support/
Calendar offline: http://www.google.com/support/
Docs offline: https://docs.google.com/
Scripting for Google Apps: OK, this takes a little bit of reading and tech-savy use, but if you manage it, the power is unbelievable. Self-grading quizzes, forms that email you, and more. Read more about this at my March 2011 blog entry.
Forms: I am amazed at how easy forms are to create and use with Google Apps. You can link that form right to your Google website to create a powerful online tool for registrations, surveys, quizzes and more. Combine that with the spreadsheet features of scripting and conditional formatting and you are in control! (For Example: Conditional formatting in a spreadsheet will turn a spreadsheet cell a certain color if a condition is met.)
And the changes keep coming...
You can always keep current with new updates and Google Apps features from this site: http://whatsnew.googleapps.com/