Enduro - normally a longer lap with timed tests in each lap you have a set time to do each lap and need to arrive on time to avoid penalties
Sprint enduro - shorter laps more like a special test go as fast as possible over a set amount of laps time added together for results
Hare and hounds - normally 3 hours multi lap do as many laps as poss in the time
Gets confusing because I noticed the American hare and hounds it totally different, it seems like they have 1 bike which is the Hare and then the rest of the bikes are the Hounds