Using a timer

I wanted to jot down a few ways I've been using a timer during school time.  I know there are plenty more, but these are the few ways I've been personally using a timer.

• Of couse you can use a timer for time outs, but how about using it schedule a "time out.'  By this I mean, taking a break.  Sometimes when we're in the middle of either a big project or tough lesson, it's great to set the timer for 10 minutes and say we're stopping when it goes off.  At least you know there is light at the end of the tunnel.
• On the other hand, you can schedule how long the break is.  I know for me taking a break for "a minute" to do something else can end up being 45 minutes.  Setting the time for 15-20 minutes helps me get back to what I was doing before the "tyranny of the urgent" takes over.
• Needless to say, there is the usual timed math speed drills or reading.  I just started doing some timed math facts drills with my dd trying to get those facts into memory instead of counting in her head (at least it's in her head and not her fingers!  That's one step down.)  Doing a set of number of problems per day for a set period of time can demonstrate how mastery is coming.
• My dd can also be slow to do work because she's playing around.  I know no one else has that trouble.  I sometimes try to keep her on task by having her race against the timer.  I think it works better as a game or challenge than as a punishement (get it done or else.)  It can be as long as "I'll give you five minutes to finish that copywork," to "Can you finish those 4 math problems in one minute?"

If you have been using a timer in some interesting way, please share it.  I'm always open to more ideas!