Doctor Who has been around for 50 years. You read that correctly. That’s a whole half of a century. Since its launch in 1963, the BBC's sci-fi TV show has garnered fans across countries and forward in time. The Doctor has changed in appearance many times in his tenure on the air, but one thing is true: the fans continue to be drawn to the series, which has always shown some of the most inventive science fiction writing on television.

Here at Ars Technica, we want to help fans celebrate. Ars is giving away two sets of Doctor Who merchandise to two lucky people. Here’s what you’ll find in each package:

TARDIS PRIZE PACKAGE

A copy of A Plague of the Cybermen, by Justin Richards with a signed bookplate, a copy of The Dalek Generation by Nicholas Briggs, and·a copy of The Shroud of Sorrow by Tommy Donbavand.

TIME LORD PACKAGE

Doctor Who, featuring Matt Smith, Blu-ray DVD Giftpack: Seasons 5, 6, and 7.

Though we would like to open up this sweepstakes to all Ars Technica readers, you must be at least 18 years old and a resident of the 50 United States and District of Columbia to participate this time around.

NO PURCHASE NECESSARY. Click here for full rules. This promotion is in no way sponsored, endorsed, administered by, or associated with BBC.

How to enter

Here’s all you need to do to have a chance to win one of the prize packages: simply share your love for Doctor Who by commenting on this post. You can tell us who your favorite Doctor is, what episodes make your best-of list, or how you got hooked on Doctor Who in the first place. Winners will be selected through a random drawing and contacted by e-mail.

The key thing to remember is that by entering a comment on this post, you can enter to win. Also, don't forget that Ars Technica subscribers are automatically included in the sweepstakes. Again, winners must live in the 50 U.S. states.

The sweepstakes begins Monday, April 15 at 9am CT and closes Sunday, April 21 at 9pm CT. Allons-y!