To test this, I'll track how genes affect attitudes during the 2012 US Presidential election by running several surveys of twins. Why twins? Well, there are two kinds of twins: identical twins (called monozygotic, or MZ) and fraternal twins (called dizygotic, or DZ). MZ twins share 100% of their DNA, but DZ twins share only about 50% of their DNA just like normal siblings. Every twin is born around the same time as his or her co-twin, so each pair of twins shares a common upbringing. If politics is mostly about upbringing (as traditional theories would have us believe), then fraternal (DZ) twins should be just as similar on average as identical (MZ) twins. But if genes do play a role in political attitudes alongside upbringing, then DZ twins should be less similar to each other than MZ twins, since MZ twins share more of their genes. So by tracking attitude changes during the election, if the attitudes of identical twins change together more than the attitudes of fraternal twins, this would suggest that genes play a role in political attitude change.
Secod, Genomes Unzipped put up a very complimentary review of openSNP. I just went in and added a bunch of phenotypes for me. I'd say openSNP is one of those attempts to bridge the space between the type of people who find 23andMe a bit overwhelming, and those who are comfortable using plink and phasing their genotypes.