Save this script and make a new mail rule with the action as running the script you just saved. This will upon getting new emails play a random song from your iTunes playlist for 25 seconds upon getting new emails for your email account in Mail.app.
on run
set volume 4
tell application "iTunes"
set shuffle of user playlist "Music" to true
end tell
tell application "iTunes"
play (next track)
delay 25.4
tell application "iTunes" to pause
end tell
tell application "System Events"
set visible of process ("iTunes") to false
end tell
end run