Quick and dirty today, I just wanted to touch on the idea of cueing the head out effectively from a solo/trading situation.  A couple of quick thoughts:

1.  Know and hear the song you are playing
The key to cueing the band effectively is to know where you are in the form at all times.  This means you should  try to always hear the melody and/or chord changes no matter what you are playing.  Nothing is worse than giving a cue at the wrong spot in the form.  Notice how I set up the simple vamp type sound and give the bass/pianist a clear look at the end of my last four in the video above (around 1:27), which leads me to my next point.

2.  Give a clear que
The Maestro 
Just like in a conversation there is a balance in improvised music between saying what you want to say, and listening to what someone else is saying.  In the case of transitioning from a drum solo or trading situation into the head out, cueing is generally the drummers responsibility.  In other words, you have to make your intentions really clear to the band so that they come in with you at the right time.  This is a situation where you have to say what you want to say, and to say it clearly.  Try to play something that unambiguously says that you are done soloing, and try to look up and make eye contact with the band.  For some inspiration on how to que a band, listen to the end of just about any Art Blakey solo ever.  If the que doesn't work...

3.  Just play some time and try again
Play some time, establish a clear link with the band and try the que again.  The more slick you are about covering up the mistake, the less impact this will have on your audience and the bands confidence, so try not to make a big deal out of it.  Remember, in improvised music sometimes the most exciting moments come from mistakes.

For more on how to recover from getting lost, Todd Bishop also has a great post at his blog "Cruise Ship Drummer!".