In Brazil, Colgate teamed up with hotel chain Marriott to remind guests of the country's water shortage by alerting them not to waste water when toothbrushing. They did this with a simple image of a child standing in a parched field, that lined the basins in hotel bathrooms, capturing guests' attention just at the place where they brush their teeth.

The campaign, by Redfuse Y&R New York, ran in hotel rooms across Sao Paulo and Recife, cities greatly affected by the lack of water in the past year. The resulting publicity video, seen here, was launched on March 21 (World Water Day), resulting in 4.8 million impressions in a 24-hour period.

We'd love to see what an idea like this would yield in other drought-stricken areas, like California.