Its like 3 day eventing but only on one day, and with only one cross country stage (ie. No steeple chases or roads or whatever were in typical "three day events", i'm pretty sure that's even changing the 3 day events now). At pony club generally you have dressage first thing in the morning, then you do cross country, then a lunch break then show jumping.
Its a full day and can get a little hectic, but its fun.
I think the only actual 3DEs that we have in Australia anymore are in Sydney and Adelaide, I could be wrong though.
Awsome. . I really like the sound of 1 day eventing .. .