The pattern for the download zips is:
http://download-codeplex.sec.s-msft.com/Download/SourceControlFileDownload.ashx?ProjectName=*projectNameHere*&changeSetId=*setIdHere*
So for the current build as of 7/28/2013 11:33 CST the link is
http://download-codeplex.sec.s-msft.com/Download/SourceControlFileDownload.ashx?ProjectName=nuget&changeSetId=2764f6c71ea206a60eb136c27c04005975712c19
You must include the changeset id and there is no automatic way I know of to find the latest id. Getting the id's themselves is easy, just click the History button and the changeset id will be in the address of the changeset you choose.