Simplify the following text for a Grade 12 native English-speaking person.
Original: Other events held at the circuit include a round of the MotoGP world championship , the Australian-based V8 Supercar championship in 2005 , attracting crowds of over 250,000 spectators , and also the final round of the A1 Grand Prix in 2006\/2007 .
Simplified: Other events held at the circuit include a round of the MotoGP world championship , the Australian-based V8 Supercar championship , and also the final round of the A1 Grand Prix in 2006 and 2007 .