ASP.NET host not applying most recent code?

So I'm working on a web app that I'm making frequent code changes to. Starting earlier today I realized that changes I made, both in the .aspx pages and the codebehind weren't being served up. I looked in the files on the server and they're current but when I surf the page I'm getting behavior from the previous version. Haven't seen this before and I'm befuddled as to what to do... I tried both publishing the changes directly from VS as well as FTP'ing the files myself, no difference.