Pencil and Paper Games is devoted to games you can play with nothing more than a pencil and a piece of paper (some of which can be played on the site, for those who do not have access to a pencil and paper, or remember what those are.) [more inside]
PuzzGrid is a lightweight, fast game of forming associations, which is, ahem, "based on" the BBC's Only Connect. Hundreds of grids to play and you can submit your own, too! (The BBC site has a few dozen more, in a fancier, louder flash app.)
Regex Dictionary - for those times when you want a web-based dictionary you can search with regular expressions.