Many of us are lucky to own a half-decent mobile phone, one with 64k colour displays and processing chips fast enough do more than organise your address book.
That's why there are Java 2 Platform Mobile Edition, or J2ME games available. Most phones come with a bunch of crappy ones you'll never play, so why not have one there that you can start up and actually enjoy while training or listening to your girlfriend talk about clog-shopping.
Enter Dweller, a game that's pretty much ideal for this purpose. It's a rogue-like that has you controlling an adventurer -- a warrior, wizard or ranger -- through a series of progressively more difficult dungeons.
Like any good rogue-hack, there are magical items and your character grows stronger as you level. As you descend further into the dungeon, the monster become increasingly harder and the items get better. By about the 6th dungeon level, you'll be drinking your healing potions sparingly and wishing you'd picked up all those mushrooms of health on the above-ground level.
It's not complex by any means, and the controls are the simplest of any rogue-like you'll play. This makes it easy to get into, the learning curve almost non-existent for the seasoned NetHack, Angband or ADOM player.
So, if you own a recent phone (we got it working on an E700, although it ran slowly) download Dweller and give it a try.
Here's the main site:http://www.roguelikedevelopment.org/dweller/index.php
If you want to grab it using WAP on your phone, point your mobile's browser here:http://www.roguelikedevelopment.org/dweller/index.wml
Note the above link is for mobile phone browers only.