Interactive Fiction Then and Now
Flipkin writes "Interactive Fiction was immensely popular in the 80s and believe it or not has a strong, albeit small, following today. MobyGames takes a look at the origins and history of Interactive Fiction and where it is heading." These games really were some of the best I've ever played.
Try Metamorphoses and Photopia. The former is known for its diverse ways of solving the puzzles; the latter is known for its nonlinear plot, touching story, and controversial lack of influence over ultimate outcomes. (Slight spoilers in the Wikipedia entry.)