Any advice on leg numbing during sitting? It happens at about 20 minutes every time lately... either in half lotus (a traditional position that i would like to honor), or with one leg laying in front of the other, or indian style... doesnt matter, my left leg goes numb. sitting up in a chair doesn't seem conducive to a meditative state and laying down i just fall asleep. id really like to do some intensive and very long blocks of meditation (advice on this would be appreciated also) but im not sure how to approach this severe distraction and get past it.
I feel your pain!  That was a huge problem for me for years!  There is a cure, thankfully.  There is some trial and error involved, but if you persist, you'll figure it out.  First, some background.  What you are experiencing usually has to do with how your butt is making contact with the cushion.  There is a big nerve center in either of your two butt cheeks.  They are located just slightly below where the bone pokes out.  When you press on that place for long periods of time, it causes the "pins and needles" feeling.  In fact, your entire leg will usually go numb first - the tingly feeling is the nerve "waking" back up.

There are a couple of ways to overcome this problem.  The take away from any of these methods is that you want to take pressure off that area:  


One way people do it is by using a higher cushion.  The idea here is that if you are off the ground a bit more, you are less likely to sink back and onto that nerve center.  You also create a natural incline with your legs.  Your thighs slope up to meet your hips.  Of course, while this will help relieve the nerve pressure in your butt, it will also eventually result in knee pain as your legs are taking more of your weight.  I tried this for a while by stacking two cushions sort of like this  ->  o\  (if that graphic makes any sense).  
Another way is to lean back a bit.  Actually, you should be doing this anyway (it helps eliminate back pain as you are less likely to lean forward).  Leaning back helps shift the weight more onto your coccyx.  You are going to feel a little weird at first - almost like you are falling backwards.  I think this is because there is a tendency for your chin to raise.  Just make sure you are keeping your neck straight.  
The method that worked for me had to do with how I was setting up on the cushion.  A lot of people plop down right in the middle of the zafu.  This is a bad idea.  You are throwing all of your weight down right on those nerves.  Personally, I set up right at the very edge of the zafu with just my coccyx coming down on the cushion.  Those bothersome nerve centers don't even make contact with the cushion at all.  I also incorporate points 1 &amp; 2.  My cushion is a little higher (maybe about five inches) and I do lean back just a bit to keep my weight coming straight down into the cushion.


Hope this helps!  I know how annoying it can be!!!