I think that's a great idea. The ability to do creative things like this is the "silver lining" of having so much money in the bank (which, as I mentioned above, is something I generally consider a risk, or at best a hedge.)
I'd love to hear your ideas about how this could work, and when we should start doing it (it's probably way too early?) either here or on meteor-talk.
This will definitely require more than the two minutes of thought I put into this post, but. . . Large companies like Adobe, Microsoft, etc, often sponsor projects that will serve as good marketing for whatever initiative they're trying to push. Something similar could work once you see projects out there. In the spirit of openness you could setup and initially fund a non profit similar to Apache Software Foundation with a board that decides where the money goes. Doing something like Google's Summer of Code might spur some interesting projects. Or maybe even set aside the cash and do some sort of community voting contest thing. Like: "Build something awesome and win up to X in no-strings-attached cash, voted on by the internet." Put in caveats like it has to become a full time project, etc.
I'd love to hear your ideas about how this could work, and when we should start doing it (it's probably way too early?) either here or on meteor-talk.