(Brad Davis/The Register-Herald) Crew members Devin Dempsey, left, and Drew Maxey begin building the starting line area as they and others prepare a moto-cross dirt track inside the Beckley-Raleigh County Convention Center in preparation for the Tristate MX Indoor Championship Series Thursday afternoon. Running tonight and Saturday at 7:00 p.m., the two-night dirt bike racing event is open to area participants of all ages and classes including beginner and youth, with proper gear and their own dirtbikes required. Sign-ups will begin today at the Convention Center at 10:00 a.m. and on Saturday at 9:00 a.m. This will be the first of four events for the Huntington-based series, which will travel to Lexington, Kentucky for their next event two weeks after this. Potential riders will be checked for safe equipment and asked to sign waivers.