Cultivated oyster mushrooms are available year round, though foraging is best in the fall and spring. If you're interested (and not yet a pro), contact a local foraging expert like Wildman Steve Brill. And remember to always ask permission when you forage on private property. If you'd like to cultivate your own, Gourmet Mushrooms will get you started, and is a great place to learn more fungus facts (for example, that mushrooms live on dead matter—yum). And for more 'shroomy fun, check out this time-lapse video of oyster mushrooms as they grow.