Martina Surprise Auctioneer, Raises $15K

Sports legend Martina Navratilova surprised guests at a charity auction in Maryland on Wednesday by standing up and offering a one-on-one tennis lesson with herself, raising $15,000, reports TMZ.

Navratilova was so moved at the Pam Shriver Silver Tennis Ball auction for cystic fibrosis that she spontaneously stood up to offer the unexpected auction item.

"I was happy to support Pam at her charity event last night," Navratilova tells TMZ. "In these economically tough times, I know how much every dollar counts,"