Complex sentence: In the past, dirt has been spread over the oval and it has been used for Sprint Car racing, even these events have drawn over 100,000 spectators, a crowd aalmost unheard of in Sprint history.
Split into simpler sentences: In the past, dirt has been spread over the oval and it has been used for sprint car racing. Even these events have drawn over 100,000 spectators, a crowd almost unheard of in sprint history.