300
Back in '96 I had a bad foot (heal spur) and had been walking with a limp for a year and a half. In December (about half way through my season) my whole leg started hurting very bad but I had no idea why. On the night of December 19th we had leagues and I showed up in a lot of pain in my leg. I don't know if the pain helped me focus but my bowling was on that night. I bowled a 300 the first game, a 210 the next game and a 193 the third game for a 703 series. The next day I had my leg checked out (for the leg pain, I already knew about the spur) and found out that I bowled a 300 with a heal spur in my heal and a blood clot that ran the entire length of my leg. I was in the hospital for a while after that.
BTW, this was a church league and about the 7th frame I'm totally trying to focus on anything other than what I bowling so that I didn't panick. This old man walks up and looks up at the board and says "you got one heck of a game going there, don't mess up and you could roll a 300". I wanted to flatten him but as I said, it was a church league.