wavesailor,

Check it out at http://demo.keetup.com/

This demo have the next features:   

1-An easy visualization for notifications
2-Advanced search with live results
3-Fast posting for status, photos, events, questions (with ajax)
4-Filter of circles of friends
5-Meetups (this module is great)
6-Sharing into facebook and twitter

You can also check out the elgg demo http://socialus.keetup.com/

This is fully responsive and also has very important features that doesnt come by default with Elgg. 

@gushbellino This page (https://community.elgg.org) is fully responsive and uses Aalborg Theme that comes by default with Elgg. For the examples of the Elgg-based sites, please check https://community.elgg.org/showcase that is exactly meant for posting Elgg sites worth sharing. This thread is from the time showcase didn't exist yet.