I was pretty good with the old Hula Hoop back in the day. As that well-known songstress Shakira once said: "the hips don't lie". I could throw and catch a ball and how difficult can it be the twirl the ribbon on a stick?
You're mixing up rhythmic gymnastics with artistic gymnastics. Artistic involves the Balance Beam, Floor, Vault and Uneven Bars. It was previously called plain old women's gymnastics.

The Uneven Bars, that sounds dangerous, surely someone would have an old spirit level knocking around?
They're also known as the Asymmetric bars, the higher one about 7ft10in from the ground and the lower one, 5ft3in. During a routine a gymnast must move from one bar to the other at least twice, by doing a simple squat-on where the gymnast puts her feet on the low bar and jumps to the high bar or in more difficult ways by doing flips from one bar to another.

Don't they have some brilliant names for those flying leaps? They remind me of those possums in Australia and New Guinea, arms and legs splayed wide, looking like they have just been impaled on a windscreen.
Yes, take your pick: Shaposhnikova, Hecht transition, Shootover, Straddle back, Pak Salto and then some of the release moves with a particular favourite the Tkatchev. The first 't' is silent.

That sounds like a Russian author?
The gymnast swings down from handstand, rotating around the bar, letting go once she approaches vertical, soaring backwards over the high bar and grabbing the bar again on the other side. This skill can be performed in the tucked, piked, straddled or laid-out position although the most common is the straddle.

What about the other one, you know for the red-haired people?
A Gienger starts from a giant swing. The gymnast comes down from handstand, swings under the high bar and lets go of the bar as her toes rise above it. Then she does a backwards flip with a half turn in either the tucked, piked or laid-out position and recatches the bar, continuing her momentum in the direction she came from. The most popular shape for a Gienger is piked or laid-out.

The competitors always look really young, are they about eight or nine years old?
To compete at Rio a female gymnast must have a birthdate before January 1st, 2001 corresponding to an age of 15 years and eight months.

It takes some bravery to do that Balance Beam and it'd make a great field sobriety test instead of the breathalyser.
The beam is just under four inches wide and some of the routines are breathtaking, literally if you are a man watching the mid-routine straddle landing.

I wonder if there'll be many 10s?
You're thinking of the old days under the Start Value (SV) scoring system. In 2006 this system was significantly overhauled. Under the new code of points, there are two different panels judging each routine, evaluating different aspects of the performance. The D score covers difficulty value, element group requirements and connection value; the E score covers execution, composition and artistry.

Come again?
The most visible change to the code was the abandonment of the "perfect 10" for an open-ended scoring system for difficulty (the D score). The E score is still limited to a maximum of 10. The sum of the two provides a gymnast's total score for the routine. Average marks for routines in major competitions in 2016 generally stayed in the mid-teens.