Have you seen Florian Schliessl's modules? The central module is pnProfile - an alternative profile module similar to the new core module or AdvProfile (which actually has become the new core profile module ;-) ). pnProfile offers dropdowns, textfields aso.
To cut a long story short: Florian has released a bunch other modules. A list can be found in his NOC profile.
PostBuddy is a module that copies a very popular function of mySpace aso - you can make people your friend and display a list of your friends in your profile. Cool, eh?
Has anybody tried pnConnections? It sounds like a cool module.
Did you see that Bernd Plagge adopted pnCommerce and released a working version? Contact him, if you are interested in cooperating with him! pnCommerce could use some cool new templates.
And pnCommerce has a young competitor! The development team has released a first beta of ShoppingKart. They are very active and keen on making ShoppingKart a cool module. IMHO their templates also lack beauty - but it's a first beta. ;-)
Robert Gasch and a user named "bones" announced to start working on a successor for PostCalendar - I'm really looking forward for that one.
But the grandmother of all calendar modules also has a competitor: crpCalendar. A neat little modules that's made to display a list of event dates - if you don't have too many of them it could fit your needs.
Did you see that Treverj is working on a cool Postnuke based Web 2.0 community site? Read: Project Updates.
Mark West released a new version of EZComments and added Akismet support. Akismet is the spam detection API of Wordpress. So EZComments sends all comments and trackbacks through Akismet to find out if it's spam or not. If you are working on any module that's been spammed - check out the Akismet module API and integrate its features into you module.
JÃ¸rn Wildt released a new content module that keeps content in a book like way and is made for team work. It's called CoType and should also serve as an example for a .8 implementation.
Hilope's Scribite is not only a module that adds the WYSIWYG editor of your choice to Postnuke modules. If you look deeper into the possibilities of for examples Xinha you will certainly never work on any site without this module. BTW: The initial development of Scribite was sponsored by the German Postnuke foundation. ;-)
Forgive me if I forgot your cool new module - this article wasn't meant to be complete. I wanted to give a little overview over what's going on right now. If you are working on something and you are looking for help or you even released it already - write your own article. I am sure it's interesting for all of us.