A couple random ones to share:
"We're off like a herd of turtles!" -Mr. B, 7-8th grade band teacher, joking around, or so I hope.
"The longer it takes, the longer it takes" - Mr. Trochil Senior High school band teacher. Just think about it a little and apply something to it. I usually say this over and over to myself when I'm in a nordic ski race. The longer it takes for me to get up this hill, the longer I have to wait to use the bathroom when I finally finish the race.