As a 'bit of fun' at the Ring, we have a challenge to see whether we can do the whole lap in a single gear (once under the gantry of course).
1st/2nd/3rd are useless as you can't get above 105mph, 6th is useless as it won't pull up the long hills, 5th is almost perfect except for one or two corners where you drop to below 50mph.
4th is the winner if you really had to drive the whole circuit in one gear.
The other 'fun' exercise we do is to artificially set ourselves a specific RPM limit - so no more than 3000/4000/5000/6000/7000rpm.
7000/6000 is easy and is like driving a 3.0 or an e34 M5, with plenty of torque/power over a few 000rpm, 5000/4000 means forever changing gear to use the bit of extra power. 3000 is doable, but you lose the 'rocket' effect out of corners as you never get into peak power curve.
The upside of all of these 'fun exercises' is that it shows how much difference the right gear makes to the performance and the fuel economy (as low as 6mpg, or as high as 14mpg)
It also shows you don't have to drive at 10/10ths on track to have 'fun'.