Its called "Frozen Bun Run" out @ Bethal Island, I dug up some info, you can find it below:
Jan. 1 - Bethel Island Frozen Bun Run, by the Bethel Island Chamber at Rusty Porthole, located at Boyd's Harbor o Piper Slough. Now in its 24th year, this event is for demented souls who feel a need to go water skiing on New Year's Day, & others who might like to watch them. Waterskiing starts about 9 a.m., they provide the towboats and ski equipment if you need it. Entry fee is $10, there are awards for male & female best costume, oldest, youngest, best skier, best wakeboarder, best barefooter, traveled farthest & best overall presentation. Porthole has breakfast buffet starting 8 a.m. & lunch buffet starting at 11 a.m. 925/684-3220.
-= peace =-