I have an interest in memory systems, which I use for learning foreign language vocabulary, technical information for my job and lots and lots of random information. I have read just about every book on mnemonic systems which I could get my hands on, and have gradually got better at practising and applying the systems.
For mnemonics, I use a 'journey' system, more or less as described by Dominic O'Brien. The main differences from my own system to Dominic's is that I tend to be less reliant on people for forming images, and rely more on objects for my peg words.
I also swear by the flashcard program SuperMemo, which I use for memorising long term information. I use the palm version, which means that I can carry it around everywhere, and memorise stuff on the bus, in bed, waiting in queues, and whenever else I have time to fill. It automatically retests you on information and schedules revision intelligently, and it provides a good measure of your learning progress and how well your mnemonics are working. I am currently transitioning to using the open source Mnemosyne software for spaced repetition.
For a few months I've been experimenting with BrainTrainingGames - especially the dual n-back task. I've tried a lot of different websites and games, and recommend cognitivefun.net as the site with the best selection of games for those who really want to stretch their mental abilities.
I appreciate all the good work you've been doing here. Please email me at firstname.lastname@example.org ASAP if you don't mind blowing your secret identity (to me) for a good reason.