How did you get into making videos with Lego?
Lego bricks have always seemed top be a part of my life (thanks to my parents) as I was attracted to the Trains, Space, and Pirate themes that reflected my natural childhood interests. I started animating Brickfilms when I was 12 years old because my parents were gracious enough to buy me the Lego Stephen Spielberg Movie Maker Set for my birthday. 
This was a consumer-affordable set with a custom low-res Logitech webcam and basic animation software. Remember that at that time, digital cameras were expensive and not very prevalent. Having a simple system that I could experiment with and learn the fundamentals of animation was essential. At about the same time, Lego® started manufacturing their Star Wars branded line, and I was immediately hooked. Being a very geeky kid, Star Wars was the catalyst that bonded all my interests together, so I started making little brickfilms and just ran with it. I became entwined with learning how the Star Wars movies were actually made, and then attempting to replicate that on a miniature scale. 
Where do your story ideas come from and how might parents generate ideas with their kids?
I have always had a vivid imagination, and had been acting out my own stories way before I had a digital camera. I can remember one particular instance when I created a story with my Lego® bricks over the course of a 3 day period. In my head, I acted-out this 3-act story that took place on top of a city train, in an underwater city, and then ending on top of a skyscraper. However, I remember feeling very disappointed at the end of my imagined adventure because I could never re-tell or share the miniature drama I had brought to life on my bedroom floor. That realization led to my desire to capture the story to enjoy later, and filmmaking is the natural extension of that. 
I think parents should go with whatever feels natural to both them and their child concerning story creation. As a kid, I loved to make things up in a spontaneous manner, and I’m not sure that structuring the stories in a storyboard-type way with my parents would have worked. Structure was already abundantly prevalent in school, and I used my animations and Lego bricks to escape that. I would have felt as if my parents were placing my imagination inside a rigid box with limited room to experiment (and experimentation is where all the fun and learning happens). Unfortunately, I recognize that I suffered a little bit from a lack of structure in my storytelling abilities, and had to learn that through trial and error. 
However, that is certainly not the only way to go. If a child thinks structurally and wants to go in that direction, then by all means I think that the parent should support that. They may suffer in the opposite direction though…(excelling at structure but having a limited ability to think spontaneously and adapt to changes). It’s all a trade off. I believe predominantly supporting the child’s natural strengths is a win, and then gradually introducing them to their weaknesses builds up a great foundation.
What advice can you offer parents who are looking to make Lego videos with their kids?
The first piece of advice I have for parents trying to create brickfilms with their kids is to allow them to experiment and fail. I cannot express how crucial this is so I’ll try to elaborate. It’s so easy for us as adults to immediately see what the “right” or “correct” way to do something is because our brains have already developed and we’re drawing on a lifetime of experience. No one wants to see a child founder so our natural instinct is to help them…almost to the point of doing it for them. This may be helpful with other tasks like a golf swing, but creativity is somewhat random and needs room to be spontaneous. 
Remember that the child is experiencing all of reality for the very first time, and needs to develop the confidence to do things independently (that’s what Finding Nemo is all about!). Simply forcing or telling the child how to accomplish a task doesn’t allow them to figure out all the nuances associated with that task. This inevitably leads to the “let me do it” line so often repeated by young children…and can often deteriorate into disinterest and frustrating resentment. Luckily, due to the democratization of the new technology, there is almost no downside to allowing a child to make as many films as they want!
I think this is extremely important because I’ve seen the unintended side-effect in adults attending college. In some of my film school classes, I worked with students who suffered from mental roadblocks and hangups. Some couldn’t seem to write a basic script for their movie because they were so focussed on making it “perfect”, and other times, entire projects fell apart because of their rigid attitudes towards a piece of work. 
It was in college that a Dr. Robert Carr gave me the most important piece of wisdom concerning this topic. His suggested method to creativity was to write down an idea (good or bad) on an index card, and then toss it away behind your shoulder. The “tossing” was an integral part to the exercise because once the idea is written down and can’t be forgotten, it allows the mind and body to “let go” of the previous idea and think of something new! After all the ideas are flushed out of your head, the index cards can be stacked and read through without any frustrating mental discourse. Then the ideas can be re-organized, mixed together, or thrown away entirely in a very fluid way. One tiny element of a terrible idea might be combined with a good idea to create an extraordinary new concept that you’d never considered before! This taught me that the actual learning comes from the process, not the end result. Creativity is messy and non-conformist. If you try to contain it, you kill it. If you force it, you smother it. Animation is inherently a slow, grinding process that requires great patience and persistence. Since a child’s attention span is notoriously short, these qualities need to be introduced in a way that makes them worthy of attaining in the child’s eyes. First, watching documentaries about animation with children really helps. I would suggest this Ray Harryhausen documentary or this original Star Wars trilogy documentary. I think the best way to go about brickfilming with children is to animate along side them at first. So, the parent could animate their own car or character, while the child does their own thing in the same shot. The child will often try to imitate the parent instead of being told what to do. At the end, the comparison is often a sharp contrast and the child will want to replicate and surpass the parent’s efforts. Language is important too. A parent expressing excitement at their own patience and abilities creates a longing in the child to rise to that level. Allowing the child to play “director” also puts them in a position of power and boosts their confidence. Basically, whatever you can do to stimulate the child’s imagination and self-confidence is a good thing. 

The two links below are videos of Alex’s animation workshops with parents and their kids!
This is a link to the slides Alex presented at his animation workshops.
And here is a link to a video tour of his studio that was filmed for a UK video game convention.