PDFShift - Convert any HTML documents to high-fidelity PDF using a single POST request
GitHub Visualizer - Enter user/repo and see the project visually
Tcpdf - TCPDF: Open Source PHP Class for generating PDF documents
Gource - Gource is a software version control visualization tool.
pdflayer - Free, powerful HTML to PDF API supporting both URL and raw HTML conversion. Unlimited document size, lightning-fast and compatible PHP, Python, Ruby, etc.
The GitHub Matrix Screensaver - Latest commits from GitHub visualized Matrix-style