1/ ride no handed for more than 10 seconds?
Yes, but it scares me unless the bike is especially stable.
2/ pull a wheelie getting the front wheel more than 6 inches off the ground?
I think my wheelies are always smaller than that.
3/ pull a wheelie and keep it up for at least 20 yds?
No.
4/ hop both wheels off the ground at once?
Yes, with lots of effort.
5/ do a proper bunny-hop: pull a wheelie then push down on the bars to bring the back up (i.e. hop with out the use of clipless pedals)?
Not really.
6/ track stand for more than 6 seconds?
Yes with quite a lot of bar turning and wobbling, if that counts.
7/ while riding along, reach down and pick a tennis ball up off the floor?
I'm not an orang utang.
8/ bike surf (i.e. one foot on the centre of the handle bars, the other on the saddle, both hands off the bike)?
No thanks!
9/ endo (i.e. hit the front brake to lift the rear wheel more than 6 inches off the ground)?
Yes, this is the easiest one (as long as the brake works well).
10/ endo-turn (as above but turn the bars so that you land with the bike pointing more than 90 degrees from the original direction)?
I often correct the position of my bike by endo-turning, but don't think I could manage 90 degrees in one go.
11/ take off or put on a rain jacket while riding along?
Possibly, but I don't want to.
Bonus points:
12/ skid stop on a fixed
Don't do fixed.
13/ ride out the saddle on a tandem
Don't do tandem.
14/ ride a unicycle?
Don't do unicycle.
One to add:
Ride one bike while pushing another and change gear via down tube levers.