and now in hours as the tributes from jimmy kimmel and conan and others still come in and rumors still flying that jay leno will at last show up on the late show with david letterman as one of his finale guests. but mostly the clock now ticks down till dave wraps up his career as a late night talk show host a little longer then johnny carson and the tonight show . and odds are there will be tissues reached for tonight . plus will jay leno be one of the finale guests to sit and talk with dave . as clock ticks down to the end of an era david letterman finale show tonight.