I'm researching Dillman lineage, of course. I currently trace a Dillman ancestor back to 1752 or so in Rheinland-Pfalz, Germany. I'm a member of the Dillman Family Association which has a major reunion every 2 years. See the website at http://www.dillmanfamilyassociation.org for more details.
I am also researching Theisen, Williams, Hengel, Dark, McMurry, Thurston, Day and a host of other names as well. Regions include southern Indiana, Louisiana, South Dakota, Pennsylvania and more in the US, and southwestern Germany and the UK in Europe.