We present a system for designing and displaying grid-based document designs that adapt to many different viewing conditions and content selections. Our system can display traditional, static documents, or it can assemble dynamic documents “on the fly” from many disparate sources via the Internet. Our adaptive layouts for aggregated documents are inspired by traditional newspaper design. Furthermore, our system allows documents to be interactive so that readers can customize documents as they read them. Our system builds on previous work on adaptive documents, using constraint-based templates to specify content-independent page designs. The new templates we describe are much more flexible in their ability to adapt to different types of content and viewing situations. This flexibility comes from allowing the individual components, or “elements,” of the templates to be mixed and matched, according to the content being displayed. We demonstrate our system with two example applications: an interactive news reader for the New York Times, and an Internet news aggregator based on MSNNewsbot.