The National Debt Clock in Manhattan hit $10 trillion earlier this week causing a “rollover” problem. This is when the data model (or in this case display) is no longer large enough to cope with the size of the required data.
The most famous rollover problem was of course the millennium bug in Y2K but there have been plenty of others though, including a GPS rollover in 1999. Forward thinking organisations such as The Long Now Foundation number years with a preceding zero so as to anticipate the Y10K rollover.
The engineering solution to the National Debt Clock rollover has been to drop the dollar sign from the display and order a larger clock.