I bought my raspberry pi a few months ago and played with it a lot at first and then put it aside until I finally came up with a use for it. I installed Debian, nginx, and wrote a small php script (run via a cron job) that can check a url to see if it is live. If the pi finds that the server is down, then I have it send me a text message to alert me so that I can respond as quickly as possible. If you are interested in having your site monitored this way, let me know. I also just made an obligatory lego case after having a cardboard one for the last couple of months.