I love this quote from the Quinn author Simon Härtel: "Quinn is an implementation of a popular falling-blocks game which, according to the Tetris Company, must not be named here." We've mentioned this game before as "...one of the most beautiful applications on the Mac." Version 3.5 continues to look great and finally brings Quinn into the Universal Binary age.
One of the coolest things about Quinn is its support for network play, allowing you go head-to-head against other players. This version also opens up some new customization options, so if you're missing your old-school (not) Tetris experience, you should give Quinn a look
Quinn is a free download from Simon Härtel.