Before we forget, Quake was once huge on the Net too. (Did you hear about how people looking for porn sites used to complain about Quake pages showing up in their search results? Oh, never mind...) Now superseded by a new generation of upstarts, there are nonetheless numerous add-ons for id's ageing darling.

Two single-player maps worthy of mention are James Bond 007 and Marioquake. The first is a 'total conversion' - that is, a game that offers a suitably different kind of play than conventional Quake. It has spying and stuff. You'll love it. Marioqauke, by contrast, is odd. In the words of its author, "Basically, it's what happens when the Quake guy retires from his job of hunting demons of death, then drinks too much beer. Heh." Quite.

The point of this feature is not, of course, to merely promote the individual maps and add-ons listed so far. As noble as that premise might be - they are, genuinely, fine free downloads - the real issue is a little more subtle.

Essentially, it's a reminder. If you own a high-profile game, it could be that someone, somewhere, has created special levels or add-ons for it. If it's a title by id, or those using their engine, there will almost surely be goodies to find. The number of playable levels for Quake 2 far exceeds the quota offered by id's miserly map designers, while Half-Life can almost double in size after a few hours' download time.

Seek and ye will, in all probability, find. You know it makes sense.