Stimulus Act of 2008 - Do Not Throw Away!

Today in our mail we received notice 1377 from the IRS. It informed us (as if we didn't already know) that we will be getting a nice check from the IRS sometime in May. This is not to be confused with any money that may be owed to us as a tax return. This is, in fact, part of the Economic Stimulus Act of 2008. You probably got one of these notices too. In a big red-outlined box and in red capital letters it informed us what was enclosed - a message from the IRS - and exclaimed (I know they exclaimed it because of the exclamation mark), DO NOT THROW AWAY!

Funny, that is exactly what they are hoping I'll do with the actual check. They want me to go out there and spend it (throw it away) so that I can do my part in stimulating the economy.

Ha ha! I'll fool them. Phil and I have decided that the money allocated for our existence may go to stimulate the economy but we want to take the $300 allocated for Eden and save it for her. So, here is my question to all you money-savvy readers. What would be the best way to take $300 (it will likely be a bit more because we are giving her a portion of the tax return too) and save it for the next 18 years? Savings bond? Mutual fund? CD? Keep in mind that we aren't what you'd call "active" investors. We would prefer something that we could leave alone for a while and watch it grow (after the economy has been stimulated sufficiently, that is). So, give me your advice!