I just finished the Videlectrix online graphic adventures, Peasant's Quest and Dangeresque Roomisode 1.
Peasant's Quest was a nice pretty long adventure that was very much like the old Sierra games from the 80s. It even contains some pretty weird puzzles with weird logic like those old games, but in this game the weird logic puzzles were optional.
Dangeresque Roomisode 1 was a really short adventure that captures the feel of early 90s adventure games. It really managed to capture the feel of LucasArts and Sierra adventure games at the same time. I'd love to see a full game done in this style, but with a point and click interface.