Where's my backslash gone?

Your special characters are in the wrong font table that is loaded by default! Printing them using a different character set will bring them back!

\documentclass{minimal}
\begin{document}
  \texttt{\char`\\}\\
  \texttt{\char`\{}\\
  \texttt{\char`\}}\\
\end{document}

See Why do lower case mathcal letters show up as random symbols? for some help as to how to print a font table.

As Yiannis wrote, it's the font table. However, using fontenc, you can get them to show up as you want.

\documentclass{minimal}
\usepackage[T1]{fontenc}
\begin{document}
\char`\\
\char`\{
\char`\}
\end{document}