Passion Play

Wine investment funds, mainly based overseas, offer another route. Diversification eases the risk, but funds usually charge steep fees and require a minimum investment often in the tens of thousands of dollars.

Race-car fans don't need as much to spin their passion into an investment. The (SCARX Quote)StockCar Stocks Fund requires a $250 minimum investment and offers a broad portfolio of stocks linked to NASCAR, from sponsors to dependable Dow names such as Exxon Mobil (XOM Quote). Since its launch in 1998, SCARX has returned about 8% annually. Says fund manager Robert Carter, "It's a way [race fans] can invest in a fund that supports [what] they're interested in."

Art has long been a favorite passion investment. But one big risk with investing in art is that artists can fall out of style. "There were artists [who were] hot 10 years ago that are stone-cold now," says Michael Connors, owner of the Michael Connors Gallery in New York City. For added protection, buyers should research the gallery or auction house promoting a given artist. "There is some art out there that's not very good, but it is being marketed so well that it [appears] hot," says Connors. Of course, if you're not an insider to the art world, differentiating the hot from the not can be tricky. Do your homework, and speak to art consultants and appraisers.

Don't have $50 million to plunk down at auction? You can start with a few thousand. "Try to find the best of a lesser-known artist," says Sirolli. That was his approach when he bought the Greene. Now, however, he's fallen victim to an unexpected risk -- getting too attached. He admits, "It's hard for me to part with it."