I actually don't find this strange at all anymore. I applied to two programs a year ago (Dec 2011) and on Nov 2011 got an email from 1 program at 8 pm on a Saturday with an attached letter of admission. The other emailed me on a Friday before classes started on the following Monday to offer me admission (into a program on the other side of the country!)
Both programs never send me any communications, and when asked why it took so long I found out that it almost always meant the majority of the adcom was for my application, but only one or two were against (usually higher ranking folks) and thus they kept me on file until those people were no longer on the committee! Really really strange politics....anyway it's been my luck haha