M/Monit is a great front-end to monitor a bunch of servers running the free and opensource monit tool. Unfortunately, the frontend, M/Monit is priced at roughly 65 Euros for monitoring just 5 hosts and up to 500 Euros for monitoring an unlimited amount of hosts. The developers are fair, in that they say they would make M/Monit free for non-profit by donating licenses - however, unless you are a legally registered non-profit and are instead just a mushroom trying to manage your fleas, you have no chance of getting the "non-profit" tag and will have to dish out 500 Euros for an interface.

The following patch will disable the expiration of the license and will turn M/Monit in an unlimited version.