Ask HN: Anybody have experience with building hobby robots?

Hi guys, I've notice a recent post outlining some activities hackers can do apart from writing software. Recently I've taken a liking to building small hobby robots on my spare time.

I recently chanced upon a site of the Society of Robots. The author gave a helpful tutorial on how to go about building your first robot. I was wondering if anybody here has had experience building robots on their spare time. Would love to hear your 2c.