Communicate Coughing -- If you try the Communicate Lite demo mentioned in TidBITS #199, and you leave it connected but idle in the background, it will make a slight coughing noise every five minutes to let you know you are still connected, much as AppleLink does. The reminder helps you to avoid running up a phone bill or running down a PowerBook battery. If you don't like the sound, you can turn it off, pick another one, or increase the time between reminders.
Single Time Machine Backups
Tired of Time Machine running all the time? You can turn it off in the Time Machine preference pane, but still initiate a single backup by choosing Back Up Now from Time Machine's menu bar icon. Of course, your backup is much less likely to be up to date, but Time Machine won't be taking any resources while you're trying to work.