Are you talking about showing off tools, or approaches, ideas, experiences?
I have found the test community full of people wanting to talk about all of those things, but because most of the cool stuff is about ideas rather than a concrete end product there isn't a single repository where people upload stuff.
I find a lot of cool new stuff by following people on Twitter, by looking at sites like http://www.softwaretestingclub.com and by going to meetups and conferences. If I have an idea for something and want to get feedback, then for me what works is using Twitter or posting it on a blog, or going to a discussion forum (like softwaretestingclub, but not here - as this isn't a discussion forum), or going to a meetup. (If there isn't a meetup near you, start one?)
Sharing work stuff is harder as it tends to be confidential. But some organizations do - look at Mozilla or the Wikimedia Foundation, for some examples (I'm finding the WMF QA mailing list a great source of ideas for our automation suite at work right now).
You could also look out for things like Testathon or the Weekend Testers if what you're looking for is to be able to test in public.