I just recieved the following email from our hosting provider:
Tomorrow evening we will be rebooting this server to perform a memory upgrade. This will require breif downtime to make the changes. We apologize for not performing this maintenance outside of our normal maintenance hours, however we want to make sure that there are no surprise reboots due to lack of memory.
We are committed to making sure all users have sufficient resources, and strive to keep to that standard.
There will be a notice posted when the reboot begins, which should be around 8:00 PM EST.