The short answer is LOTS!
I love learning new programming languages. I started out with various dialects of BASIC and Z80 assembly on old 8-bit computers (Amstrad CPC, ZX Spectrum, C64, BBC/Acorn etc.) when I was about 8 or 9 years old. I'm now a professional C/C++ programmer.
Languages I use most often are:
C,
C++,
Python,
Java,
Shellscripting (Unix/Linux/BSD using bash)
Other languages I've used in the past:
6502 Assembly
X86 / X64 Assembly (with at&t and intel style syntax),
Pascal / Delphi,
ASP / ASP.net,
C#,
Visual Basic,
Javascript (with the usual html and css ),
PHP,
Lua,
Batch-scripting (Windows),
Flash/Flex/Actionscript,
Unreal engine-script,
Lisp,
Ladder Logic (for programming industrial PLC's),
Several SQL-like database languages,
Several bespoke, in-house scripting/macro languages (at previous jobs).
There may be a few others that I've forgotten to include!
Many of the languages in the above list are ones that I had to learn "on the fly" for projects at previous jobs (C#,VB etc). Others (like Pascal and 6502 assembly) were used even further back when I was at school/college. But I've been in my current (C++ only) job for almost 12 years now. So a lot of the above list have probably been completely purged from my brain!
Misc:
In recent years, I've toyed with a few novelty programming languages like:
Chef - where programs are delicious recipes,
Arnoldc - where programs are composed of Arnold Schwarzeneggar quotes,
Lolcode - where programs are written using lolcat style leet-speak,
Brainfuck - which does what it says on the tin.
Not practical or productive programming languages. But it can be a fun challenge to try to code and debug even a simple program using them!
Still learning:
I'm currently trying to learn Ruby and Haskell - out of my own curiosity.
I also have Erlang, R, Rust, Scala, Clojure and Go on my ever-growing TODO list.
And I'm attempting to teach my kids to code using Scratch and PythonTurtle.