add shell games

content/services/shell.md

@@ -102,6 +102,29 @@ setfacl -Rdm "u:www-data:rx" ~/public_html/cgi-bin
 You can change your login shell using the
 [burble.dn42 service portal](https://svc.burble.dn42).
 
+### Classic Games
+
+The shells have a number of classic text games installed:
+
+**[Colossal Cave Adventure](https://en.wikipedia.org/wiki/Colossal_Cave_Adventure)**  
+*Get lost in a twisty little maze of passages*  
+```$ adventure```
+
+**[Trek](https://en.wikipedia.org/wiki/Star_Trek_(1971_video_game))**  
+```$ trek```
+
+**[NetHack](https://en.wikipedia.org/wiki/NetHack)**  
+*The original time sink*  
+```$ nethack```
+
+**[Zork](https://en.wikipedia.org/wiki/Zork)**  
+*Zork 1, 2 and 3 are available in /usr/local/frotz/*  
+```$ frotz /usr/local/frotz/ZORK1.DAT```  
+```$ frotz /usr/local/frotz/ZORK2.DAT```  
+```$ frotz /usr/local/frotz/ZORK3.DAT```
+
+Take a look in /usr/games for more text games.
+
 ### Cron, Batch and Services
 
 Cron and other batch or long running tasks are ok, but be a nice neighbour