Events can have invoices, expenses and even deposits (for donations etc).
You can use Categories to keep track of finances for your Events.
When setting up your Event, rather than use a generic "Event" category, Add New Category specifically for the Event, e.g.
2. Expenses, Invoices and Deposits
When recording any debits or credits for the Event, use the special Category you've set up. e.g.
3. Keeping Track of it all
After the Event (or even before) you can download a CSV file detailing all your Transactions.
The CSV can be imported into your Spreadsheet program (Excel, Open Office etc) and you can then sort your Transactions by Category, e.g.
Tip: Don't forget to also check in Invoices, Expenses and Deposits for items that are related to your Event/Category but have not been paid/received at the time you run your Transaction report, e.g.
Note: you can also use Categories to track expenses for Meetings (e.g. Annual General or Special Meetings) that have their own specific and special costs etc. Although no Category is allocated to the meeting itself, a Category can be added to track any associated costs or donations for the meeting.