I have a page that grabs data from a database and graphs it using flot. (BTW, If you need dynamic graphs or charts on your website and haven’t checked out flot, do it!) The database is populated by a weather station that aggregates data and records a new entry every 30 minutes. So, every hour at 0 and 30 minutes, new data is recorded and the graphs can be updated.
At first, I did a simple refresh of the page every minute to grab the new data. This works, but is annoying when you have scrolled down and are zooming in on a data set. Every minute, the page reloads and you start over.