Want to surprise someone with a cute message, without letting the person know who has sent that message. Use NoSpm. It’s a free, no-frills-attached, anonymous email outbox service that can be used to send anonymous messages online to any email address.
To start sending messages, enter the email id of receiver, subject line, mail text and hit Send button. Your mail would be delivered instantly.
I have used this mail service twice, once to send mail to a corporate mail id and other time to Gmail, I can vouch for the reliability of service. Sincerely hope that this service do not get attacked by spammers and does not shuts down like the similar free anonymous SMS service AnonTxt (that is currently down due to abuse)
Check out nospm.org