On August 16, 2000, at about 1403 eastern daylight time, a Schweizer SGS 1-34, N7679, registered to Tampa Bay Soaring Society Inc., operating as a 14 CFR Part 91 personal flight, crashed on landing in the vicinity of Zephyrhills Municipal Airport (ZPH), Zephyrhills, Florida. Visual meteorological conditions prevailed, and no flight plan was filed. The glider sustained substantial damage and the student pilot sustained serious injuries. The flight originated from ZPH, about 33 minutes before the accident. The pilot remembers departing on the glider flight; and remembers returning to the traffic pattern, but has no further recall of the events leading up to the accident. The brother of the injured pilot stated he observed the glider established on a low and slow final to runway 36, before the glider started spinning to the right. He contacted UNICOM on a handheld radio and asked them to call 911.