MigraDoc Foundation the Open Source .NET library that easily creates documents based on an object model with paragraphs, tables, styles, etc. and renders them into PDF, XPS, or RTF. 

PDFsharp is the Open Source .NET library that easily creates and processes PDF documents on the fly from any .NET language. The same drawing routines can be used to create PDF documents, draw on the screen, or send output to any printer. 

The ASP.NET MVC framework provides an alternative to the ASP.NET Web Forms pattern for creating MVC-based Web applications. The Model-View-Controller (MVC) architectural pattern separates an application into three main components: the model, the view, and the controller. The ASP.NET MVC framework is a lightweight, highly testable presentation framework that (as with Web Forms-based applications) is integrated with existing ASP.NET features, such as master pages and membership-based authentication. The MVC framework is defined in the System.Web.Mvc namespace and is a fundamental, supported part of the System.Web namespace. 

The ASP.NET AJAX Control Toolkit is an open-source project built on top of the Microsoft ASP.NET AJAX framework. It is a joint effort between Microsoft and the ASP.NET AJAX community that provides a powerful infrastructure to write reusable, customizable and extensible ASP.NET AJAX extenders and controls, as well as a rich array of controls that can be used out of the box to create an interactive Web experience. The AJAX Control Toolkit contains more than 30 controls that enable you to easily create rich, interactive web pages. 

Trident (also known as MSHTML) is the name of the layout engine for the Microsoft Windows version of Internet Explorer. It was first introduced with the release of Internet Explorer version 4.0 in October 1997; it has been steadily upgraded and remains in use today. For versions 7 and 8 of Internet Explorer, Microsoft made significant changes to the Trident layout engine to improve compliance with web standards and add support for new technologies. With version 5.0 of Trident, Microsoft intends to comply with many modern web standards, and also intends to significantly update the layout engine to be more competitive and modern compared to other current layout engines. [source: Wikipedia]