Lunchclub - Curated 1:1 professional connections
Meja - Pitch your ideas, get constructive feedback!
Serendipity - Serendipity is a PHP-powered weblog engine which gives the user an easy way to maintain a blog.
Pitchdeck - Pitch Deck is a web-based solution to you create engaging presentations.
Lunch Roulette - Collaboration by grouping coworkers randomly for lunch.
GoToPitch - GoToPitch.