Hi, How do you come up with ideas (good ones :-)) for your games? What kind of creativity techniques and process do you/if you use? Please share your experience. Thank you

I find the most effective way to come up with ideas is to research things in order to create a sort of encyclopedia of source material.

Once you get a sort of holistic view of your chosen subject, the interesting parts jump out and there's all this material there to add depth.

Think of Tolkien -- he wrote some books, but he didn't just make it up as he went along, he first created this whole world with characters, a long history, entire languages, racial conflicts, and all. Eventually he saw that there were certain forces at play (Sauron, the ring, et al) at a certain time (third age) when he thought some noteworthy things could be happening... so he began writing, explaining in detail what happened.

I suspect based on my own experience, that he never thought "hmm, what should happen next?" -- the world he created told him what happened. The geography that he had in his mind told HIM what Frodo's journey would be like. He knew the Balrog was in Moria before he knew that the fellowship would end up there. Then it was just a matter of figuring out how they would escape an army of orcs and a giant demon god thing. He was just reporting on things that had already happened in his imagined universe.

That way you're never at a loss for what happened -- instead you're telling the story of this world, and you feel bad for having to leave out so much detail that you know is there, but you can't capture in your retelling.

This strategy works for any creative endeavor. I just explained how it could work for writing, but visual studies are equally effective for art, and game design could be approached either way: developing a world, then making a game out of the dramatic parts, or creating a sort of collage of games from which the most interesting and engaging mechanics can emerge.

I use this technique heavily for my game Kōtiro, and I'm documenting everything on my site for it.

I recommend the works by Roger Oech:

A Whack on the Side of the Head
A Kick in the Seat of the Pants
Creative Whack Pack

But in terms of the OP's question (coming up with original and new ideas), that isn't usually the designer's assignment. Usually he's given a genre, a technology, or a set of characters, and then he's told to come up with a game within that framework. Some designers have referred to those as "constraints" but I don't see them that way. When you're faced with a totally blank page and told to put something new and original on it, that's much harder! The Whack/Kick books can help you there for sure.

Nowadays, if I want to get really creative, I go to a museum or a science/discovery store with an open mind.

Music.
I come up with a lot of interesting shooter game ideas when I listen to jungle/breakbeat soundtracks from another games.
I get a lot of interesting stories in my mind when I remember/listen to sad orchestral music.

But sometimes the innovative ideas just come when I shake my head, lol. :D

The main point of my post is - try to do everything you can at the moment (even the crazy things) and the good ideas should get to you fast.
Research won't do this, IMHO, because it's like an answer for a question - it doesn't help you think more about the question, it just kills any thoughts about the question.

I generally look at it like this: If one in a million ideas is a great one, then I need to come up with a million ideas! Basically, I just throw random interesting ideas out there (I normally write them down somewhere) and see what sticks. If I come back to an idea I had a month ago and I still like it, then I tend to think that it might be something worth pursuing.

Go on a Wikipedian adventure. Start looking up random topics that interest you, open up every interesting link in another tab, and keep reading and skimming for an hour or two. You'll learn a lot and also possibly get some inspiration.

I usually get my best story ideas when reading other stories, and my best game ideas when playing other games. Usually I'm thinking, "What would I have done differently if I had made this? How is it the same as other things I have read/played, and how is it different? How/why does it work? What could I remove without making it work more poorly, and what could I add or substitute to make it work better? What could be changed to make it more interesting? What seeds of interesting ideas are here but weren't developed as much as they could have been, and how could I develop them further? Considering a pool of sources, how could I combine the best parts of all of them into a new concept?"

Sometimes when I'm washing dishes, my mind really gets going and I get all kinds of great ideas. Some of my best ideas have come to me while washing dishes. There's something to do with the repetive motion and minimal brain involvement that can make me relax my mind and let the ideas flow.

For me, relaxing is the trick. I feel like the good ideas are lock up somewhere in my head already, and I just need to let them come out.

I mostly deal with stories, but I do still create game ideas.

It is rare for me to be asked for an idea from scratch, but I have done in the past. Ideas are not really the issue; I keep a pen and paper handy most of the time and jot down all of the errant ideas that I have. I have a huge file full of odd ideas on my PC and I tend to take a look at them when I need to create from scratch. Often, I combine ideas from different times, as inspiration hits and makes connections, and see where it goes.

When I need an idea, I read the news, I check New Scientist and I listen to Radio Rivendell. A good epic music track will often inspire whole stories for me, as I start to 'fill in the blanks' and put a tale to the music.

For instance, I recently went to new scientist while listening to something cyberpunkish; I saw that there was a robotics company called Cyberdyne and one of their products was called HAL, which reminded me of the mad AI from Arthur C Clarke's 2001. Suddenly, I had this idea about murderous AI that might try to destroy humanity. Sadly, it had already been done...

The news can be just as bad, to be honest. I caught sight of a headline about Somali pirates and it was all I could do not to pitch The Princess Bride to the design team yet again.

The mention of Cyberdyne and HAL is actually a true story. Here are the links.
http://en.wikipedia.org/wiki/Cyberdyne_Inc._%28Japanese_company%29
http://en.wikipedia.org/wiki/HAL_5