Let me warn you up front,
this is a TOUGH tricep exercise. It combines two of the
very best bodyweight tricep exercises you can (other than
dips) into an alternating-rep (inset superset) exercise.
You can do this one with
your feet on the floor to make it easier, just fyi...I'm
using a bench to set my feet on because I'm insane and
wanted to make things as hard as possible, apparently.
Anyway, the set up as I
have it requires a barbell loaded with a couple of 45's
and a bench (if you want to use a bench). You can pretty
much use any sort of rail or solid bar instead of the
setup I have here but this is just what I needed to use
for my gym.
I set the loaded barbell
up against the uprights of the rack and set the bench
a few feet behind.
So set your hands on the
bar (overhand grip about a foot apart).

Set your feet up on the
bench and get your body into a pike position.

Lower yourself down into
the bodyweight tricep extension. Basically, this looks
like an overhead barbell tricep extension only instead
of moving the bar, you're moving your body.
With the body vertical like
this, it's a TOUGH exercise so make sure your triceps
are up for it. I would recommend starting with your feet
on the floor the first time you do this one (I'll see
about filming that version in the near future here).

Extend back up to the top
position.

Now straighten your body
and come down into a close-grip push-up. The difference
with this movement from a regular close-grip push-up is
that instead of coming straight down, you move forward
and down.
Then as you come up, you
come back into the pike position again so you're not just
pushing straight up, you're pushing up and back. A little
double trouble for you!
Now just repeat these two
movements, alternating reps of each exercise until you're
toasted. The video shows this quite well.
Your triceps will be swelled
up to what feels like twice their normal size after this
one!
And let me know if YOUR
exit from the exercise is as graceful as mine :) - You'll
see it in the video...