NASCAR heads to Bristol, Tenn., for the weekend with Greg Biffle the new Sprint Cup points leader after his win at Michigan last week. Television coverage of NASCAR events begins with Nationwide Series practice at 7 this morning on the Speed Channel. Sprint Cup practice and the Happy Hour Series practice session follow on the Speed Channel. Things get serious in the afternoon with Sprint Cup pole qualifying at 2 on ESPN2 and the Nationwide Series race at 4:30 on ESPN. The Irwin Tools Night Race, the Sprint Cup feature, will air on ABC at 4:30 p.m. Saturday.