Instead of donating your sperm to a sperm bank, why not donate it to this meaningful art project? As the Web site says, the Sperm Cube is "collecting 1 cubic meter of sperm preserved frozen in a transparent cube. A collective artwork, international, open to all, universal." No matter whether you're black, white, American, Arabian, or whatever, all human sperm looks the same and it all mingles together in the Sperm Cube. This site is originally French, so the English translation isn't quite accurate. For instance, the measurements on the front page aren't correct – one cubic meter of sperm is certainly not 1,000 liters, and it does not way 1 ton.
And if you don't have the incentive – or the sperm – to donate, that's okay too – you can make a cash donation and become a shareholder. After all, anyone would gladly want a certificate to display to visitors that they are a shareholder in the Sperm Cube Project.