There's nothing particularly special about next Tuesday - that's the 17 October.
Sarah finds out about blog Britain from Dan Snow
It's just an ordinary day, but you can make it special by keeping a blog or diary for just one day.
The aim is to create the biggest ever blog throughout Britain, and by taking part you can contribute to a day in history.
Organisers hope it will provide a useful archive for generations in the future.
If you want to find out how to take part, follow the link below to the History Matters website - you can get all the information you need.
Please note - this is not a BBC event but we've included all you need to know to take part
How you can get involved
First, record a diary of your day on October 17. It can be anything from 100 to 650 words long.
Log on to the History Matters website (via the link above or to the right), and follow the instructions on how to upload your blog/diary
Diaries can be uploaded from 17 to 31 October 2006
Urge friends, family and colleagues to do the same!
Watch the History Matters website for details of how the archive can be accessed in the future