I'm monitoring the site 24h/day and it's been working for 20+ hours, although at times it's still timing out.
Virwox has their server hosted on a server that has "DDOS protection" which basically means they get attacked like any other site, but they will block certain IPs. Those blocks usually last about 6 to 8 hours, after which they are lifted.

Current access time averages out to about 5~10 seconds, which means the DDOS is probably still going on, but less than before.