I'll watch most FIA racing, including F-1, FIM Moto-anything, The Cooper Challenge races(gotta love the Mini's), European Semi races, Australian racing, even some soccer(er, futbal). Basically anything with a high energy announcer with an accent will catch my fancy and warrant at least a look.
I will not watch very much American football, and no Basketball, NASCAR. I watch some Baseball(I also played as a youth until an injury riuned my throwing arm). Minor league Baseball is pretty good, especially in person. Never got into Hockey. The announcers for American sports are so (Bleep) boring I can't stand it. Basketball has been so basterdized for the sake of dollars that it barely resembles the original concept, forget the original rules. I saw a NASCAR race live in 1996(free ticket), all I needed to get my fix. It has fallen into the corporate greed machine also. I will watch vintage NASCAR, but today's is so.... blech. NHRA is watchable to me, but so much better in person. I will occasionally take a jaunt to the local dirt track and spend some hard earned cash. I have guns and enjoy some occasional target shooting, just to keep the skills from fading, but hate watching it on the tube.