8-month-old and standing in his crib...how can I get him to sleep?

I'm going through a very similar situation at the moment with my 10 month old. All I can suggest is that you keep doing what your doing (great work by the way!). It's just like training them to go to sleep on their own. There's not a whole lot else you can do unless you tied there legs up!! (jokes :P). Good luck. Just keep going (not too often) and just lie him back down, etc. He will tire of it eventually.