FamilyTreeDNA.com is running a $39 sale for a basic test of male line Y-chromosome DNA. I encourage any male-line descendant MAGNER to take advantage of this sale. 12 markers can be a great first-step test, which you can later follow with upgrades for potentially more genealogical detail. My own Y-DNA pattern is uncommon, so any MAGNER who matches me 12 out 12 may be a valuable connection.

Here's the link:
http://www.familytreedna.com/landing/Y-DNA12-Promo.aspx

My own DNA test matched several men of Irish descent. My great-grandfather was adopted via Orphan Train, but his birth certificate listed a Dr. James MAGNER as his father. He then appeared on the 1900 census (in an orphanage) with the surname MAGHER. Due to transcription errors and spelling variation, possible surnames are Magner, Magher, Maher, or Mahar. His adoptive family believed the name was Wagner, but I find that to be the least likely.