My blog is a custom ruby/rack application, and has been crashing randomly every couple of weeks. I sometimes don't notice for days, and I'd like to be notified immediately if it happens. 

What's the best way to do it? I'm running Centos 5.3, Nginx, Passenger, Rack, etc. 

I've considered figuring out some way to email myself the tail of my error log, as that would help me catch EVERYTHING, not just that one app (it would tell me of missing links, etc). Is there an easy way to do that?

Thanks!