Under Profiles, there is a "Phone Only" option which will eliminate the ring or vibrate for incoming messages, but not stop them.
For me, I have all my email forwarded to my
addy and my mail server is accessible from the web, so I can go turn off the forwarding pretty easy, but not something you would want to do 3 or 4 times a day. You could also go into the BIS if your mail is polling and delete your email address and add it back, again not something you want to do 3 or 4 times a day.