We have a large variety of direct sale fundraising ideas, and you'll want to browse through those thoroughly, because the great majority of them will be perfect as extra fundraisers for your non profit organization's event. And don't feel that you have to limit yourself to just one - there's no reason you can't get several fundraisers going at the same time, and really watch your profits soar. If you have a wide range of products available for people to purchase at your non profit organization fundraising event, then not only do you increase your chances of having something for everyone, but you also have a much greater chance of getting people to buy more than one item, which can really boost your overall fundraising sales numbers.
You'll definitely want to take advantage of any break times or intermissions during your event, and use those to push your sales team forward into the audience and get your supplementary fundraising efforts moving. This will not only help get profits up, but it will also help introduce members of your non profit organization to the community that they serve, and those bonds can help ensure greater amounts of donations and support in the future.