Roomvine - Chatrooms for real life venues, neighborhoods and events
InviteRobot - Instant subscription for paid Slack communities
Spectrum - Browser-based app to visualize the frequencies of an audio file.
SlackPass - Subscription access to anything with Slack
CityBugs - Improving cities to make them a better place to live in.
Grapevine Surveys - Grapevine is an online survey tool for employee surveys.