neo.tax - automated R&D tax credits for startups = extra month of burn
Online-RSVP.com - Beautiful online RSVP for wedding & other events. Create an online invitation, track your guests responses.
BurnoutIndex - Check your burnout risk. Backed by science, forever-free.
RSVPify - A powerful and awesomely customizable platform for selling tickets online for your event.
SendRecurring - SendRecurring allows you to setup, send, and maintain scheduled email reminders.
Eventbrite - Discover Great Events or Create Your Own & Sell Tickets