One of my first breaks in IT was freelance work on the Science Museum website back when they didn't know anyone who could make web sites. I was in my early 20s and someone I knew from the pub had a mum who was a curator. She asked her son if he knew anyone because "web developer" was a fairly uncommon skill!
I eventually got crowded out by a proper agency but I've still got clients in the culture sector that I got from word of mouth from that. My company is still doing stuff as a direct result of that contact.
I worked on Collections, a couple of special topic sections (Fusion and Science Museum in Japan), Exhiblets... I later helped with the touchscreens for the opening of the Wellcome Wing and then I started working with the NMDC - who are still a (hopefully happy) client.
I eventually got crowded out by a proper agency but I've still got clients in the culture sector that I got from word of mouth from that. My company is still doing stuff as a direct result of that contact.
(I'm 49 so do the maths yourself)