Last year I collected some giant sequoia (AKA giant redwood) pine cones here in France, I've just extracted the seeds (must be on the order of 500...) and put some in water. These are notoriously hard to germinate but let's see!
It is said that you can offset a lifetime of CO2 emissions by growing a single one of these trees, since they are the largest trees in the world, but that's an oversimplification. Still pretty cool though.