AncestrybyDNA's new Euro-DNA 1.0 genetic test -- Genealogy is a huge hobby and genetic testing services have emerged to sell to people interested in their ancestral backgrounds. Most have focused on the easier to test Y-chromosome (direct male line) and mitochondrial (direct female line) tests, but those only tell you so much. In contrast, AncestrybyDNA offers tests on your autosomal or "pan-genome" DNA which give you a statistical picture of your whole family tree.
They've now introduced a test for Caucasians that can tell you your admixture as broken down into four groups:
Northern European subgroup (NOR)
Southeastern European (Mediterranean) subgroup (MED)
Middle Eastern subgroup (MIDEAS)
South Asian subgroup (SA)
Their paper introducing the service gives lots of interesting details on the genetic background of Europeans and white Americans. In general, Europeans appear to be the most homogenized of all the continental-scale racial groups, so I suspect that customers are typically going to be underwhelmed by the findings: E.g., "You're 50% NOR, 35% MED, 10% MIDEAS, and 5% SA." That's probably not going to satisfy somebody who puts a lot of emphasis on his ethnic identity as a Walloon or Slovak or whatever. But, the write-up is most interesting.
The entire website is loaded with neat stuff, but it's important to keep in mind that this autosomal DNA analysis is still a long way from being 100% accurate. For example, here is one family where the mother was measured as 22% black and the father as 0% black. The test reported that the three children were 15%, 2%, and 6% black by ancestry -- not bad, but not great either. There's a certain amount of statistical noise in the results, so the website offers a lot of caveats -- for example, a lot of Jews who know all four of their grandparents immigrated from Poland take the test and show up as a few % Native American. So, don't put much weight on small numbers.