Only when I mix them. I have some ugly CGI scripts in the boneyard written in VB4 which produced Javascript which produced HTML. *shudder*
Anyway, for programming languages, it's Python all the way, right now. Since I'm mostly working on webapps, Javascript might be included. Markup: HTML. Query: SQL.
From time to time, I'll fix someone else's broken code in Java or Perl or C or VB/VBA. But it's rare.