https://www.getponga.com/ - easiest way to send email notifications from any script. Just launched it today.
Most projects I work on involve email notifications, mostly internal updates to myself or other team members when some event takes place. Its always a pain for me to buy a domain, verify/whitelist it, configure a saas email offering, etc.
Ponga takes seconds to get going, just get an api key and start sending emails in seconds. Has been super useful for me and some friends that are already using it.