Examples — Recent
Examples of powerful LaTeX packages and techniques in use — a great way to learn LaTeX by example. Search or browse below.

Program Correctness: Example
An example that shows how to write proof outlines in LaTeX.
Hans-Dieter Hiep

Typeset the source code documentation for MetaFont
This project typesets the source code documentation for MetaFont. The mf.tex source file was extracted from MetaFont’s WEB source code after processing via a Web2C-based workflow.
Graham Douglas

Understanding floats
A document that tries to explain my understanding of floats within LaTeX documents. Here's a brief blog post linking to the read only version of this: http://goo.gl/G8j9KT.
Vince

Root Hair Cell in 3D using TikZ
A TikZ figure using the beamerposter package. It shows an idealised 3D root hair cell, and its projection onto a 2D rectangular domain. The auxin symplastic pathway is indicated by purple arrows and the longitudinal auxin gradient by a shade in the 2D-domain; influx and efflux permeability arrows, indicating a polarising process, are respectively depicted in orange and light-blue. Switching fluctuation is represented by dark green arrows.
Víctor F. Breña-Medina

Carta
Carta a secretaria academica
Peter Góngora

A longtable + tabularx example
The xltabular combines the functionalities of longtable and tabularx.
LianTze Lim

Typesetting scholarly critical editions with reledmac
reledmac is a package for typesetting scholarly critical editions, replacing the established ledmac and eledmac packages. The package supports indexing by page and by line numbers, and simple tabular- and array-style environments.
Maïeul Rouquette (uploaded by LianTze Lim)

Series de Fourier
Este ejemplo demuestra como se puede sintetizar una señal periódica de "diente de sierra" partiendo de las Series de Fourier, utilizando sumas de funciones senoidales que van desde la que tiene la frecuencia fundamental de la señal hasta sus armónicas. Para ello se usa el paquete pgfplots y el comando \pgfplotsinvokeforeach{,...,} y luego se suma de forma acumulativa para formar la función \sumacurva, definida como una variable que parte del cero (0).
Ramón

Biber works!
Biblatex with biber as backend
Oleg Soloviev