Is there any bills to nationally legalize marijuana?

I'm not aware of any bills which would legalize marijuana nationwide, and any such legislation would be highly irregular.  While federal laws can, and do, criminalize the sale of certain substances nationwide, I am not aware of any federal law that has authorized the sale of a given substance nationwide; to the best of my knowledge, that has always been left to individual jurisdictions (sometimes down to the county level).  Thus, for example, while the sale of alcohol is no longer illegal under federal law, there are counties in which it is prohibited by county law.  Any federal law legalizing marijuana nationwide is sure to face a constitutional challenge on states' rights grounds.