I've written a couple of scripts over the years to email me when certain things happen on things I don't own, and as long as you're cool with a few false positi

I've written a couple of scripts over the years to email me when certain things happen on things I don't own, and as long as you're cool with a few false positives, it's not too difficult. Say you're waiting for something on a website to become available. I'd look for some language on the page about availability that's likely to change when available. I don't know what they're going to change it to, but I know that it'll (probably change). I set up a script to run every few minutes to check that particular spot on the page. If it changes, I get an email. Maybe I got an email when it changed from 'unavailable' to 'available soon', but that's okay, that means it'll definitely work when it's available for real. There's always a chance that it won't work, but if you can reasonably assert what is likely to change, it's very easy to monitor it.