From ONMC:

NASCAR will run three test sessions on Thursday, January 31 (9:00 am-12:00 pm, 1:00 pm-5:00 pm and 6:00 pm-9:00 pm) and two test sessions on Friday, February 1 (9:00 am-12:00 pm and 1:00 pm-5:00 pm). Admission to the grandstands will be free for all sessions. Fans that purchase tickets for the Auto Club 500 by January 31 will also be granted access to the infield rooftops during testing. Fans who have not purchased their tickets for the February NASCAR race weekend can still gain access to the infield rooftops with a $5 donation to the NASCAR Foundation. Additionally, members of California Speedway’s Hard Card program – season ticket holders who have renewed their seats for 2008 – will have access to a special question and answer session with fan favorite driver Robby Gordon after Friday afternoon’s testing session.