This is a really quick post to get a useful resource out into the Opsmanosphere.
Back in OpsMgr 2007 days, one of the assets I carried with me everywhere was Daniele's OpsMgrEventIDs spreadsheet. Daniele does a good job of explaining usage of a spreadsheet like this. I would use this day in day out to decipher OpsMgr environments, or use as a look up for questions stating EventIDs but no other information e.g. Source, description. It's also very useful when breaking down the top events collected by OpsMgr.
The tool used to extract this event log information is Event Log Explorer.