Chebyshev's 200th birthday on Sunday, May 16 will be marked by an online symposium based at the Leonhard Euler International Mathematical Institute in St. Petersburg: https://eimi.ru/chebyshev200/. Talks run 1-6 UK time and at 4:00 Trefethen will speak on "Fourier, Chebyshev, and Chebfun". See http://www.chebfun.org/examples/fun/Birthday.html.