Solo gaming comes in all shapes and sizes. Today's shapes look like this :)
Attacks of Opportunity
http://attacksofopportunity.blogspot.com/search/label/lonely%20fun
Which morphed into this:
About How to Host a Dungeon
http://planet-thirteen.com/Dungeon.aspx
And if you have a few minutes to kill and want to do some crawling or even show someone new to the hobby how much fun they can have, just start them with this:
Solo Dungeon Bash
http://www.bookranger.co.uk/SoloDungeonBash/SoloDungeonBash.html
And with such a simple form you can re-load this a few times until a bigger challenge is desired.
Enjoy!