A stunt is an unusual and difficult physical feat, or any act requiring a special skill, performed for artistic purposes. In the Grand Theft Auto series, since GTA III (2001), stunting is a popular pastime among the community, with feats usually involving various vehicles such as bikes, motorcycles and cars. Players who perform such acts are usually rewarded with an Insane Stunt Bonus, which is equal to an amount of cash, depending on how insane the stunt is.
There are three 'ranks' of Insane Stunt bonuses, the higher ranks increasingly difficult to achieve. Firstly, the Insane Stunt bonus, which is the easiest. Next the Double Insane Stunt bonus, which is a little harder. Finally, there is the Triple Insane Stunt bonus, which is fairly rare without special conditions or cheats.
In Grand Theft Auto: Vice City Stories there are two new stunt jumps called "Flaming Insane Stunt" and "Quadruple Insane Stunt", the former is awarded by doing an insane stunt that causes the vehicle to catch fire at some point prior to landing, usually on take-off while the latter is a fourth rank of normal insane stunts.