Most of my Android work belongs to a client, and so I can't use it as a portfolio. Below are a few demos.
They're not on the market because they're demos, rather than complete games. I don't wish to simply add another Tetris clone, and it takes a long time to design the fun into a new game (even assuming the game concept works).
Nor have I worked out how I want to provide the back-end (support, etc) that Google requires before publishing.
I'm a programmer, not an artist. If I was trying to sell these as finished apps, I'd commission someone eles to provide the art.
It's really easy to install them without needing the Market (go to this site in the phone browser, click on the link, click on the download notification in the status bar).

Permissions required: none (it's just graphics and the built-in motion sensor).
Find out roughly what time it is without taking your phone out of your pocket. Tap three times on the outside of your pocket, and the phone vibrates:
| Minutes past the hour | Vibrations |
|---|---|
| 0-14 | 4 |
| 15-29 | 1 |
| 30-44 | 2 |
| 45-59 | 3 |
Keeps your handset dry in rain, preserves night vision, probably more discreet than blatently getting your phone out.
Permissions required: vibration.
Start the application, tick "run in background", press BACK.
The trigger is 3 taps on the back or front (not the sides), within five seconds of each other.
To stop the background service again, open the application and untick the tickbox.
It detects the motion of the phone, so won't work if the phone doesn't move (for example if it's on a hard table).
Tap detection is inaccurate at the moment.
False positives when tapping on the screen in other apps while the background service is running.