Context menu video joining app

I often just want to join a couple of wmv or avi files. So I was wondering is there is an app that just adds a context menu to windows like "Merge Files".

So I just mark the files I want to merge and it will sort them alphabetically(Or I do it..) and merge them. So I won't have to start a program every time.

Or Porhaps adding a merge drop point. So I just drag and drop the files I want to merge to the merge drop point and they will merge to one file in the current directory.

Is there such an app?