I can't give you actual monitoring scripts because I didn't write some of them and I don't have permissions to hand the ones I didn't create. Also, you can learn more by writing them yourself. I can, however, tell you where you can look for ideas.
Hard Drive space monitoring - Send out an email to yourself when your HD space falls below X percent. Here's a link to an article on it by Greg Larsen. www.databasejournal.com/features/mssql/article.php/3080501
Cluster Checking - Notifies you if your cluster failed over to a node that it should be on. Use the SERVERPROPERTY('ComputerNamePhysicalNetBIOS') function to double-check your server name. If the name is supposed to be ServerA, but is ServerB, send yourself an email / page telling you that the server is running on the incorrect node.
DB Growth History - Monitors your DB growth over long periods of time. We run this job weekly. Create a Table to hold DBName, CurrentSize, LastSize, the date of the check and the percentage of growth. Then use Master.dbo.sysdatabases and Master.dbo.sysaltfiles. You'll have to do some math to get your sizes in MB or GB. I believe the sizes in sysaltfiles are in KB.
And lastly, don't forget to set up SQL Server Performance Condition Alerts and an Operator with an email/pager so you can monitor preset events in SQL Server. Look up "Alerts" in Books Online.