About a month ago I got some citric acid. Since then I've tried putting it on and in various things. Chocolate was strange, Strawberries were good, but my favorite has definitely been watermelon:

(If you're not as big a fan of sour food as I am you probably want to start with less of it than in the picture.)

My cousin, who doesn't normally like watermelon or consider it worth eating, tried it with citric acid and found himself eating the whole thing, rind and all.