As you might have noticed, the server this site (virtuemart.net) resides on, has problems. The filesystem is corrupt and this is the reason for the downtimes.
It's not that we need better hosting or another provider, but we just need some time to move the site to a completely new dedicated server. But it's holiday time! So I hope we can do this next week, so please be patient even if more downtimes may occur.
Please bookmark the download site on forge.joomla.org, so you can still download VirtueMart if this server should be down: http://forge.joomla.org/sf/go/projects.virtuemart/frs .