Kepler
Cornell Big Red
There were stories of coaches going to the local bar and pulling guys out to fill out the roster on game day. Mind you, this was in the very, very early days of college football. And it wouldn't surprise me if it happened with other sports as well.
Horse Feathers (1933) parodied this brilliantly, but there were credible stories about schools doing this back to the 1910s, and by "schools" I don't mean the SEC and Big Ten I mean Harvard and Yale.