As many people have said, some go to the fountain of knowledge to drink... while others merely gargle. Some want to swim in it. Some just sail their toy boats on it, and don't actually partake of it. Some even go to pee in it, and foul it for everyone else.
The way of excellence, though, is to bring a canteen!
First of all, your knowledge will fade. As a friend of mine likes to say, by the time you leave this lecture you'll forget half of what I said, tomorrow you'll forget half of what remained, and in two weeks you'll deny you were even here. When you attend some way of learning something, be it a multi-semester college course or a five-minute talk, take it with you. Take notes. Buy the book. Do a practice project.
But that's just normal everyday excellence. It's just something basic you'd do any time you want to learn something. It doesn't take any daring at all.
Some say "sharing is caring" (except of course the RIAA), but sharing can also be daring. Let others drink from your canteen of knowledge. You will find that, as in the magic trick, it never runs out... and there will also be more for you.
The secret to this version of the trick, is to have the confidence that you can still be seen as excellent, in relation to others, even after they have absorbed the knowledge you bring. This can take many forms. For example, you may be so far ahead of them, that this knowledge will not let them overtake you. Or it may be outside of your primary working skill, so it doesn't threaten your ability to make a living. Or, best of all, you may be part of a trend, where you all teach each other, and you're all excellent together... including not only whatever the subject is, but in teaching as well.