Mammoth said:
That might be a dumb question, but Apple's website isn't really that great for telling me what I should know for developing games and programs.
Apple won't tell you, because they don't know what reason you will program for. All languages exist for a reason. Otherwise, we would use only 1 programming language, which we would think it would be the best.
If you want to make games, C or C++ would be your choice. (quake 3 was written in plain C. Unreal Tournament 2004 was written in C++ I think).
If you want to make professional programs, and/or programs that are capable of using the OS's sub-routines or APIs you will need Java, C++, C, or Obj-C.
My advice: Go with C or C++. They are the languages that will be your ticket to the world of professional programming.