Cowboy boots signed by two of the wealthiest men in the world will be auctioned off at the Cattlemen's Ball, which raises money for cancer research in Nebraska.

Microsoft founder Bill Gates and investor Warren Buffett have each signed boots for the auction. They'll join pairs signed by comedian Dan Whitney, better known as Larry the Cable Guy, actor Kevin Costner and country singers Brad Paisley and Charlie Daniels.

The 11th annual Cattlemen's Ball will be held June 5-6 near Doniphan. Proceeds from the event will go to cancer research, including the University of Nebraska Medical Center's Eppley Cancer Center.

Proxy bids for the boot auction are being taken online at the ball's Web site, www.cattlemensball.com. The winner will be announced June 6.