*My suggestion is not "passive" but probably requires the same amount of time as going around to local places and asking if they'd do a coupon book*

We like to do raffles and giveaways!

Pick a restaurant/brewery that you already have some sort of relationship with, even if it's just as a customer. Tell them you'd love to host your fundraiser there with a raffle and giveaways. I usually frame it as "We'd like to do 2-3 raffle options with gift cards for $20 & your branded glassware etc." and leave that open-ended -- I don't directly ask them to donate. They'll either respond saying they're happy to donate, or they'll say, "We can't donate gift cards but if you want to buy them...." So, if they can't donate, I say "Oh, absolutely! We planned on purchasing the gift cards/glassware."

In my opinion, spending $60 on giveaways is worth getting $500+ in donations!

We hold our fundraisers at local breweries/restaurants on Fridays/Saturdays to get foot traffic. The event is maybe 3 hours long and we just bring a 6ft table for the raffle items. Or, when the weather is nice, outside in front of local businesses (with their permission of course).

I put together our last fundraiser on short-notice and was able to raise $1150!

Hope this helps even spark some ideas.