If you like Tvheadend and use it a lot, why not make a donation.
The money is used for keeping Tvheadend related infrastructure going (such as this website) and also for buying test kit for development/support.
A list of significant donations is available here
Please remember that Tvheadend is a spare time project and that the time available for development varies a lot. We would appreciate if you think of donations as a way to express your gratitude of what's already been done, rather than a way to pay for features or bug fixes in advance. We all have families and day job's which are both (obviously) given priority over this project.