Now what? It's like these wacky errors pop up at just wonderful times. Usually Friday, after a significant build has just been deployed to Model Office.
Could not load file or assembly App_Web_ovgpxsa - Other posts speak of MSFT hotfixes to turning off batch build. App_Web dll's are found in the Temporary ASP.NET Files folder. So I stopped the web, app, and w3wp.exe - deleted the Temporary ASP.NET Files - and started things back up again.