I've started a brokerage account exclusively for a big hunting expenditure down the road. Some in money market funds, some in low cost index funds. Whether it's a dall hunt or a duck club membership I want to be able to pay for it outside our operating funds. A little money every month goes a long way with compounding.
We have a three month old at home and I'm going to do the same for him (along with a 529 plan). Whether he wants to buy a home, a ranch, or go on a OIL hunt in his thirties he will have the ability to do it. Timing the market is great when you are lucky enough to do so, but time in the market is where exponential growth shines.
This is a great plan until the economy and all asset classes tumble after our $35,000,000,000,000+ of federal debt comes back to bite us in the ass.