This recent campaign by Pieter-Jan Fraussen, a Belgian designer on behalf of the "stop poverty" campaign in Belgium, showcased 60 pillows with the slogan "still too many people sleep in the street." The pillows were located on the Meir, a main shopping street in the city of Antwerp.
Although this reminds me of the Israeli Food Bank Campaign, the focus is slightly different. The slogans are very similar, but they are simple and powerful. As you can see above, people stopped and interacted with the pillows, spreading awareness for the cause. The pillow directs people to sign a petition at this website as a means to make a change.
This clever guerilla promo was effective because it received coverage on several Dutch blogs and other media, and definitely got people talking about the cause. It might be a good strategy for a business to try using promotional pillows or even promotional travel kits as a practical promotion that can be creatively tied into a guerrilla marketing effort.