I came across SiteUpTime.com which does web site monitoring, as the name implies. They offer a free plan which I just signed up for to monitor The OS Quest.
The free plan includes:
1 Monitor
30 or 60 minute check intervals
4 Monitoring Locations
Email Alerts
Monthly Reports
Online Statistics
Control Panel
Web Server Monitoring (http)
Email Server Monitoring (pop3)
Email Server Monitoring (smtp)
FTP Server Monitoring [...]
Popularity: 15% [?]
