I will just echo Multipurpose on this one, if staying awake is a problem then you may have to forego the pre wo's with caffeine. Yes, that limits which ones you can take, and they may not give you insane energy, but at the end of the day (no pun intended har har) if your need to sleep outweighs your need for not dragging ass in the gym, then you know what you have to do.

You can try what semper sort of suggested, in that you could try taking a warm shower or bath after the workout (soak in some epsom salts with lavender, etc...), and make sure your post workout meal includes a good amount of carbs.

Do some cardio afterwards to burn yourself out. Usually after the gym I have a shake, then I shower, then I make my big post workout meal, but on cardio days sometimes I'm so burnt out I crash for like 2 hours before I even get my post workout meal in. Thats why late workouts usually don't bother me because if I get all my work in I even crash after my afternoon workout sometimes. Or you could just take the new jacked3d it really doesn't do shit.

I workout at 11pm 5 nights a week and I have the same problem. Even if I use a 1/4 of the recomended dose I still cant get to sleep. Im almost sure there is none out there that wont keep you up.