Microlend to a business in a developing country

Talk about your win-wins. With www.lendwithcare.org, entrepreneurs in Benin, Togo, Indonesia, Cambodia and the Philippines post their projects and funding needs online. You lend money, from £15 on up, to the business you choose, getting to (virtually) meet with the loan recipient and track the progress of the loan. The business gets up and running, you get your money back, the principle of economic self-sufficiency is strengthened (if that's your bag), and you can add "venture capitalist" to your business cards (again, if you're into that sort of thing). Default rates are less than 2% and the lending is overseen by CARE International in conjunction with local microfinance institutions, making these secure and appropriate investments.

Effort involved: no physical effort, unless your wallet's in another room.