http://manawatucarclub.org.nz/event/envirowaste-manfeild-4-5km-sealed-autocross/?instance_id=1037
4.5km autocross, which is about the longest autocross you will ever do... Basically drive round the whole Manfeild track, both front and back at once. With some chicanes to keep the speed down. Due to only doing 1 lap at a time you are much less likely to break your car too...
Do it! I will most likely be there in my E30 BMW (as WRX is in bits). Good cheap fun in a low key environment, with no requirement for a race license.
Do it!