Subcolorings and the subchromatic number of a graph. John Gimbel and Chris Hartman. Submitted to Discrete Math. pdf
Spernerís Lemma, Pouzetís Lemma, The Brouwer Fixed Point Theorem and the Theorem of (the game of) Hex. A talk Iíve given more than once that I really need to write up into a paper. In pdf.
There are others, I just havenít put them here yet.