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What GRAS cares about

community-driven guerrilla campaigns for local businesses.

    This Halloween, we’re turning the streets of Amsterdam into one giant, interactive ghost hunt — and we need your help to make it happen. We’re GRAS, a small creative team that believes in making marketing fun, bold, and unforgettable. On October 31st, we’ll unleash hundreds of glowing “ghost lights” across the city, hidden in unexpected spots. With a special light, players will discover hidden clues and secret posters — each leading them to local shops, bars, and cafés taking part in the game. The stunt will bring people together, shine a spotlight on small businesses, and turn an ordinary Friday night into a city-wide adventure. Your donation will go directly toward: Printing our special posters (including hidden, light-activated layers) Building ghost costumes for our volunteers Buying hundreds of ghost lights for players to use Covering safety, snacks, and coordination for our volunteer team Let’s make Amsterdam a spooky this Halloween.